Direct link to index.md of specific folders

[SanchitMahajan236]

I have linked the links in index.md of docs folder directly to index.md of their specific folders as all the information required is in the index.md.

Earlier, the link redirected to the folder which the user required and to access information needed, he had to access index.md of that folder. But I changed the links to directly redirect the user inside index.md file.

If any change is required, I will be more than happy to make the change.

Kindly accept this PR under hacktoberfest.

[postmodern]

This is unnecessary, since Jekyll converts the index.md files into index.html files, and linking to /directory/ is the same as linking to /directory/index.html.