Missing documentation for `strip` build variables

### Description of the bug:

I'm looking at https://bazel.build/docs/cc-toolchain-config-reference#cctoolchainconfiginfo-build-variables in order to figure out which build variables are relevant to the invocation of the strip tool. From that, it seems there are only two, `input_file` and `stripopts`. Those are not enough though, the `output_file` variable seems to be used as well, from what I can see in the source code. For example, this is from tools/osx/crosstools/cc_toolchain_config.bzl:
```
strip_action = action_config(
action_name = ACTION_NAMES.strip,
flag_sets = [
flag_set(
flag_groups = [
flag_group(flags = ["-S", "-o", "%{output_file}"]),
flag_group(
flags = ["%{stripopts}"],
iterate_over = "stripopts",
),
flag_group(flags = ["%{input_file}"]),
],
),
],
tools = [tool(path = "/usr/bin/strip")],
)
```

### What's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

_No response_

### Which operating system are you running Bazel on?

Ubuntu

### What is the output of `bazel info release`?

5.1.1

### If `bazel info release` returns `development version` or `(@non-git)`, tell us how you built Bazel.

_No response_

### What's the output of `git remote get-url origin; git rev-parse master; git rev-parse HEAD` ?

_No response_

### Have you found anything relevant by searching the web?

_No response_

### Any other information, logs, or outputs that you want to share?

_No response_

Start with the referenced C++ toolchain build-variables documentation and compare it with the strip_action definition in tools/osx/crosstools/cc_toolchain_config.bzl. Confirm which variables are used for strip actions, update the reference accordingly, and verify the documentation build or relevant documentation checks.

Written by the indexing model from the issue text.