docs: replace outdated note about build frontend and remove mention of ClearLinux (#2926)

* Remove outdated `pip wheel` note

* Remove ClearLinux reference

* Change Alpine to BSD

docs/options.md

@@ -807,9 +807,9 @@ instead.
 ### `before-build` {: #before-build env-var toml}
 > Execute a shell command preparing each wheel's build
 
-A shell command to run before building the wheel. This option allows you to run a command in **each** Python environment before the `pip wheel` command. This is useful if you need to set up some dependency so it's available during the build.
+A shell command to run before building the wheel. This option allows you to run a command in **each** Python environment before the wheel is built. This is useful if you need to set up some dependency so it's available during the build.
 
-If dependencies are required to build your wheel (for example if you include a header from a Python module), instead of using this command, we recommend adding requirements to a `pyproject.toml` file's `build-system.requires` array instead. This is reproducible, and users who do not get your wheels (such as Alpine or ClearLinux users) will still benefit.
+If dependencies are required to build your wheel (for example if you include a header from a Python module), instead of using this command, we recommend adding requirements to a `pyproject.toml` file's `build-system.requires` array instead. This is reproducible, and users who do not get your wheels (such as BSD operating system variants) will still benefit.
 
 The active Python binary can be accessed using `python`, and pip with `pip`; cibuildwheel makes sure the right version of Python and pip will be executed. The placeholder `{package}` can be used here; it will be replaced by the path to the package being built by cibuildwheel.