Rust formatter split some part of keyword to new line instead of continuing the line which can result in errors

rust-analyzer version: (eg. output of "rust-analyzer: Show RA Version" command, accessible in VSCode via Ctrl/⌘+Shift+P) rust-analyzer version: 0.3.2474-standalone (d2f17873ff 2025-05-23) [/Users/lulu/.vscode/extensions/rust-lang.rust-analyzer-0.3.2474-darwin-arm64/server/rust-analyzer]

rustc version: (eg. output of rustc -V) rustc 1.87.0 (17067e9ac 2025-05-09) (Homebrew)

editor or extension: (eg. VSCode, Vim, Emacs, etc. For VSCode users, specify your extension version; for users of other editors, provide the distribution if applicable) VSCode 1.100.2

relevant settings: (eg. client settings, or environment variables like CARGO, RUSTC, RUSTUP_HOME or CARGO_HOME)

repository link (if public, optional): (eg. rust-analyzer)

code snippet to reproduce:

//this is a very long comment text to test the line length and ensure that it wraps correctly in the editor

Actual formatted output:

    //this is
         a very long comment text to 
       test the line leng
       th and ensure that
        it wraps correct
    ly in the editor

Some characters split into multiple lines even they are not full word which can result in errors after forrmatting this code

Start by reproducing the formatting of the long Rust comment shown in the issue with the reported rust-analyzer and rustc versions. Trace the formatter behavior responsible for splitting words and verify the fix by confirming that formatting preserves complete words and produces valid Rust source.