CLN:replace single with double backticks
#36617


    doc/source/development/contributing.rst
    doc/source/development/contributing_docstring.rst
    doc/source/development/extending.rst
    doc/source/ecosystem.rst
    doc/source/getting_started/install.rst
    doc/source/getting_started/comparison/comparison_with_sql.rst
    doc/source/getting_started/intro_tutorials/06_calculate_statistics.rst
    doc/source/getting_started/intro_tutorials/08_combine_dataframes.rst
    doc/source/user_guide/categorical.rst
