feat: Add llm_friendly_source option for LLM-compatible source rendering

[S1M0N38]

Summary

This PR adds a new llm_friendly_source configuration option that addresses the compatibility issue between mkdocstrings source code rendering and LLM-focused tools like mkdocs-llmstxt.

Problem

When using show_source: true with mkdocstrings-python, the mkdocs-llmstxt plugin generates suboptimal output in llms-full.txt files. Instead of clean, readable Python code blocks, source code gets converted into confusing table format with line numbers and compressed code.

Solution

Added a new boolean configuration option llm_friendly_source that:

• Removes line numbers from source code displays
• Uses simple markdown-style code blocks instead of complex HTML tables
• Maintains backward compatibility (defaults to False)
• Works alongside existing show_source option

Changes

• ✅ Config: Add llm_friendly_source: bool = False to PythonInputOptions
• ✅ Templates: Update function and class templates to conditionally render LLM-friendly source
• ✅ Documentation: Add comprehensive documentation with usage examples
• ✅ Tests: Add test coverage for both traditional and LLM-friendly rendering
• ✅ Quality: All linting, type checking, and documentation checks pass

Usage

# mkdocs.yml
plugins:
- mkdocstrings:
    handlers:
      python:
        options:
          show_source: true
          llm_friendly_source: true  # New option\!

Before vs After

Before (Traditional - problematic for LLM tools):

<table class="highlighttable">
  <tr><td class="linenos">1</td><td class="code">def function(): ...</td></tr>
</table>

After (LLM-friendly):

<div class="language-python highlight">
  <pre><code class="language-python">def function(): ...</code></pre>
</div>

Test Plan

• All existing tests pass
• New test verifies LLM-friendly rendering works
• Code quality checks pass (Ruff, MyPy)
• Documentation builds successfully
• Feature works for both functions and classes

Fixes #299

🤖 Generated with Claude Code