docs: add related projects (#456)
docs: add related projects (#456)

* docs: add related projects

I think it may help adoption of `prettier` if
people don't have to change their entire coding
style all at once. These projects enable that.

* docs: add prettier-with-tabs to related projects

rattrayalex/prettier,arijs/prettier-with-tabs,arijs/prettier-with-tabs,Skywalker13/prettier-space-parenthesis,existentialism/prettier,rattrayalex/prettier,azz/prettier,Skywalker13/prettier-space-parenthesis,vjeux/prettier,azz/prettier,danharper/prettier,lydell/prettier,despairblue/prettier,Pajn/prettier,yamafaktory/prettier,lydell/prettier,yamafaktory/prettier,rattrayalex/prettier,azz/prettier,azz/prettier,Skywalker13/prettier-space-parenthesis,arijs/prettier-miscellaneous,arijs/prettier-miscellaneous,Pajn/prettier,existentialism/prettier,arijs/prettier-miscellaneous,despairblue/prettier,jlongster/prettier,existentialism/prettier,prettier/prettier,prettier/prettier,Skywalker13/prettier-space-parenthesis,arijs/prettier-miscellaneous,lydell/prettier,prettier/prettier,lydell/prettier,prettier/prettier,existentialism/prettier