Made the following updates to the main README file (docs/intro.rst) to improve readability and add missing information:
Changed 'Introduction' section header to 'What is wcwidth?'.
Reformatted 'Introduction' section and fixed minor grammatical issues.
Added 'Getting Started' section.
'Getting Started' section includes basic API function information, links to PyPI package, links to API documentation site, Unicode environment variable config, and pip install instructions
Added 'Helpful Resources for Contributors' section.
'Helpful Resources for Contributors' section includes instructions for making local changes to source code, updating Unicode data tables, building documentation, executing unit tests, updating requirements, and using supplemental utilities.
Made the following updates to the main README file (docs/intro.rst) to improve readability and add missing information: