Added beginClip and ednClip functions in p5FunctionKeywords

[Chaitanya1672]

Progress towards #3163

Changes:
I have added the beginClip() and endClip() functions to the p5FunctionKeywords to ensure they are highlighted like other p5.js functions in the p5.js web editor.

I have verified that this pull request:

• has no linting errors (npm run lint)
• has no test errors (npm run test)
• is from a uniquely-named feature branch and is up to date with the develop branch.
• is descriptively named and links to an issue number, i.e. Fixes #123

[raclim]

Thanks for your work on this! Despite being a temporary resolution to the issue, I'm going to merge this in as progress towards it to get this out there since this overall is a beneficial change. Thanks again and please feel free to open another PR with the long-term fix!