Add recommonmark to build deps
    
    Should fix:
    
    Traceback (most recent call last):
      File "/usr/lib/python3.10/site-packages/sphinx/config.py", line 327, in eval_config_file
        exec(code, namespace)
      File "/builddir/build/BUILD/clang-14.0.0.src/redhat-linux-build/docs/conf.py", line 41, in <module>
        import recommonmark
    ModuleNotFoundError: No module named 'recommonmark'