Rust Clippy command line not handled correctly

## Information

**VIM version**

VIM - Vi IMproved 9.1 (2024 Jan 02, compiled Jun 18 2024 19:01:23)
macOS version - arm64

Operating System:

macOS X Sonoma 14.5

## What went wrong

These options previously worked:

```vim
let g:ale_rust_cargo_use_clippy = executable('cargo-clippy')
let g:ale_rust_cargo_use_clippy = 1
let g:ale_rust_cargo_clippy_options =
\ '--tests --all-features --all-targets -- -D warnings'
```

But not anymore:

```
(finished - exit code 101) ['/opt/homebrew/bin/zsh', '-c', 'cd ''xxx'' && cargo clippy --frozen --message-format=json -q -- --tests --all-features --all-targets -- -D warnings']

<<>>
error: process didn't exit successfully: `/Users/xxx/.rustup/toolchains/1.79.0-aarch64-apple-darwin/bin/clippy-driver /Users/xxx/.rustup/toolchains/1.79.0-aarch64-apple-darwin/bin/rustc -vV` (exit status: 1)
--- stderr
error: Unrecognized option: 'tests'

<<>>
```

It seems the extra `--` before `--tests` is causing an issue. Not sure whether the problem is due to Rust version or Ale version changes.

The problem seems to be fixed when I change the following line in file `cargo.vim`:

```vim
let l:clippy_options = ' -- ' . l:clippy_options
```

To:

```vim
let l:clippy_options = ' ' . l:clippy_options
```

Hopefully, this fix will work for others, too.

## Reproducing the bug

### :ALEInfo

Expand
Current Filetype: rust
Available Linters: ['analyzer', 'cargo', 'cspell', 'rls', 'rustc']
Linter Aliases:
'analyzer' -> ['rust_analyzer']
Enabled Linters: ['analyzer', 'cargo']
Ignored Linters: []
Suggested Fixers:
'remove_trailing_lines' - Remove all blank lines at the end of a file.
'rustfmt' - Fix Rust files with Rustfmt.
'trim_whitespace' - Remove all trailing whitespace characters at the end of every line.

Linter Variables:
" Press Space to read :help for a setting
let g:ale_rust_analyzer_config = {}
let g:ale_rust_analyzer_executable = 'rust-analyzer'
let g:ale_rust_cargo_avoid_whole_workspace = 1
let g:ale_rust_cargo_check_all_targets = 0
let g:ale_rust_cargo_check_examples = 0
let g:ale_rust_cargo_check_tests = 0
let g:ale_rust_cargo_clippy_options = '--tests --all-features --all-targets -- -D warnings'
let g:ale_rust_cargo_default_feature_behavior = 'default'
let g:ale_rust_cargo_include_features = ''
let g:ale_rust_cargo_target_dir = ''
let g:ale_rust_cargo_use_check = 1
let g:ale_rust_cargo_use_clippy = 1
let g:ale_rust_ignore_error_codes = []
let g:ale_rust_ignore_secondary_spans = 0
let g:ale_rust_rustfmt_options = '+nightly-2024-03-28 --edition 2021'

Global Variables:
" Press Space to read :help for a setting
let g:ale_cache_executable_check_failures = v:null
let g:ale_change_sign_column_color = 0
let g:ale_command_wrapper = ''
let g:ale_completion_delay = v:null
let g:ale_completion_enabled = 0
let g:ale_completion_max_suggestions = v:null
let g:ale_disable_lsp = 'auto'
let g:ale_echo_cursor = 1
let g:ale_echo_msg_error_str = 'Error'
let g:ale_echo_msg_format = '%code: %%s'
let g:ale_echo_msg_info_str = 'Info'
let g:ale_echo_msg_warning_str = 'Warning'
let g:ale_enabled = 1
let g:ale_fix_on_save = 1
let g:ale_fixers = {'vim': ['trim_whitespace', 'remove_trailing_lines'], 'sh': ['shfmt', 'trim_whitespace', 'remove_trailing_lines'], 'cpp': ['clang-format', 'trim_whitespace', 'remove_trailing_lines'], 'go': ['gofmt', 'trim_whitespace', 'remove_trailing_lines'], 'markdown': ['prettier', 'trim_whitespace', 'remove_trailing_lines'], 'bash': ['shfmt', 'trim_whitespace', 'remove_trailing_lines'], 'yaml': ['prettier', 'trim_whitespace', 'remove_trailing_lines'], 'ocaml': ['ocamlformat', 'trim_whitespace', 'remove_trailing_lines'], 'python': ['ruff_format', 'trim_whitespace', 'remove_trailing_lines'], 'bzl': ['buildifier', 'trim_whitespace', 'remove_trailing_lines'], 'c': ['clang-format', 'trim_whitespace', 'remove_trailing_lines'], 'proto': ['buf-format', 'protolint', 'trim_whitespace', 'remove_trailing_lines'], 'xml': ['xmllint', 'trim_whitespace', 'remove_trailing_lines'], 'toml': ['trim_whitespace', 'remove_trailing_lines'], 'rust': ['rustfmt', 'trim_whitespace', 'remove_trailing_lines'], 'zsh': ['shfmt', 'trim_whitespace', 'remove_trailing_lines'], 'json': ['prettier', 'trim_whitespace', 'remove_trailing_lines'], 'sql': ['sqlfluff', 'trim_whitespace', 'remove_trailing_lines'], 'java': ['google_java_format', 'trim_whitespace', 'remove_trailing_lines']}
let g:ale_history_enabled = 1
let g:ale_info_default_mode = 'preview'
let g:ale_history_log_output = 1
let g:ale_keep_list_window_open = 0
let g:ale_lint_delay = 200
let g:ale_lint_on_enter = 1
let g:ale_lint_on_filetype_changed = 1
let g:ale_lint_on_insert_leave = 1
let g:ale_lint_on_save = 1
let g:ale_lint_on_text_changed = 'normal'
let g:ale_linter_aliases = {}
let g:ale_linters = {'sh': ['bashate', 'language_server', 'shell', 'shellcheck'], 'cpp': ['cc', 'clangtidy', 'cppcheck', 'cpplint'], 'go': ['gofmt', 'golangci-lint', 'revive', 'staticcheck'], 'markdown': ['markdownlint', 'proselint', 'vale', 'writegood'], 'yaml': ['yamllint', 'yaml-language-server', 'circleci', 'spectral'], 'ocaml': ['merlin'], 'python': ['ruff', 'flake8', 'pylint', 'pyright', 'bandit'], 'c': ['cc', 'clangtidy', 'cppcheck', 'cpplint'], 'proto': ['buf_lint', 'protolint'], 'xml': ['xmllint'], 'rust': ['analyzer', 'cargo'], 'json': ['jsonlint', 'spectral'], 'java': ['javalsp', 'checkstyle', 'pmd'], 'sql': ['sqlfluff'], 'ansible': ['ansible_lint', 'language_server']}
let g:ale_linters_explicit = 0
let g:ale_linters_ignore = {}
let g:ale_list_vertical = 0
let g:ale_list_window_size = 10
let g:ale_loclist_msg_format = '%code: %%s'
let g:ale_max_buffer_history_size = 20
let g:ale_max_signs = -1
let g:ale_maximum_file_size = v:null
let g:ale_open_list = 0
let g:ale_pattern_options = v:null
let g:ale_pattern_options_enabled = v:null
let g:ale_root = {}
let g:ale_set_balloons = 0
let g:ale_set_highlights = 1
let g:ale_set_loclist = 1
let g:ale_set_quickfix = 0
let g:ale_set_signs = 1
let g:ale_sign_column_always = 0
let g:ale_sign_error = '✘'
let g:ale_sign_info = 'ⓘ'
let g:ale_sign_offset = 1000000
let g:ale_sign_style_error = '✘'
let g:ale_sign_style_warning = '⚠'
let g:ale_sign_warning = '⚠'
let g:ale_sign_highlight_linenrs = 0
let g:ale_type_map = {}
let g:ale_use_neovim_diagnostics_api = 0
let g:ale_use_global_executables = v:null
let g:ale_virtualtext_cursor = 'all'
let g:ale_warn_about_trailing_blank_lines = 1
let g:ale_warn_about_trailing_whitespace = 1

Command History:

(executable check - success) rust-analyzer
(executable check - success) cargo
(finished - exit code 0) ['/opt/homebrew/bin/zsh', '-c', 'cd ''xxx'' && ''cargo'' --version']

<<>>
cargo 1.79.0 (ffa9cf99a 2024-06-03)
<<>>

(finished - exit code 101) ['/opt/homebrew/bin/zsh', '-c', 'cd ''xxx'' && cargo clippy --frozen --message-format=json -q -- --tests --all-features --all-targets -- -D warnings']

<<>>
error: process didn't exit successfully: `/Users/xxx/.rustup/toolchains/1.79.0-aarch64-apple-darwin/bin/clippy-driver /Users/xxx/.rustup/toolchains/1.79.0-aarch64-apple-darwin/bin/rustc -vV` (exit status: 1)
--- stderr
error: Unrecognized option: 'tests'

<<>>