Change codeNavigation to 'supported' for C and C++

[ashis-baral]

Why:

Closes: None

Updates the code navigation support documentation to reflect that C and C++ are supported languages.

What's being changed (if available, include any code snippets, screenshots, or gifs):

Updated supported-code-languages.yml to change the codeNavigation status for the following languages:

C: not-supported → supported
C++: not-supported → supported

This ensures the documentation accurately reflects the current code navigation support status for C and C++.

Check off the following:

• A subject matter expert (SME) has reviewed the technical accuracy of the content in this PR. In most cases, the author can be the SME. Open source contributions may require an SME review from GitHub staff.
• The changes in this PR meet the docs fundamentals that are required for all content.
• All CI checks are passing and the changes look good in the review environment.

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