Uncommented the Bootstrap section in the index.html file, which enables the Bootstrap section on the website. Also, added substantial content to the newly created md/html/bootstrap.md file to cover Bootstrap related materials in detail. Corrected the CSS title format in the md/html/css.md file for proper markdown rendering.

The instructions for installing and launching the project have been added to the README.md file. This provides necessary information for users or other developers on how to get the project running.

fix: use `setAttribute` instead of `innerHTML` to prevent XSS

fix broken mobile scroll view navigation where there were fragments starting at an index above 1 #3540

bump 5.0.2 version in build files