[Documentation] Windows Clang toolchain setup guide needed for Bazel 8.2.1

### Page link:

https://bazel.build/configure/windows#clang

### Problem description (include actual vs expected text, if applicable):

When attempting to use Clang with Bazel 8.2.1 on Windows, the toolchain fails to resolve properly. This appears to be either a configuration issue or a documentation gap, as the current documentation doesn't adequately explain how to set up Clang toolchains on Windows.

Actual behavior:
- Running `bazel build` or `bazel coverage` commands fails with toolchain resolution error
- Error message:

ERROR: While resolving toolchains for target //:hello: invalid registered toolchain '@local_config_cc//:cc-toolchain-x64_windows-clang-cl': No repository visible as '@local_config_cc' from main repository

- No clear documentation exists on how to properly configure Clang toolchain on Windows

Expected behavior:
- Clear documentation should exist explaining how to set up Clang toolchain on Windows
- The toolchain should be properly resolved when Clang is installed
- Build commands should execute successfully with Clang toolchain
**Documentation should include:**
- Required WORKSPACE configurations
- Any necessary .bazelrc settings
- Prerequisites and environment setup steps
- Common troubleshooting steps

This issue affects Windows users trying to use Clang with Bazel, particularly those moving away from MSVC or trying to standardize their toolchain across platforms.

### Where do you see this issue? (include link to specific section of the page, if applicable)

https://bazel.build/configure/windows#clang

### Any other information you'd like to share?

Reproduction case repository: https://github.com/KrishnaM256/bazel-project

Steps to reproduce:

1. Clone the repository:
`git clone https://github.com/KrishnaM256/bazel-project.git`
cd bazel-project

2. Run the build command:
`bazel build //:hello`

3. Observe the toolchain resolution error