Ignore docs/prettier.min.js when searching with ag/ripgrep/sift (#1717)
Ignore docs/prettier.min.js when searching with ag/ripgrep/sift (#1717)

This makes it easier to search through the code without getting
irrelevant results. It uses a .ignore file in order to cover at least
the three tools mentioned in the title. See the discussion here:

https://news.ycombinator.com/item?id=12568822
Skywalker13/prettier-space-parenthesis,jlongster/prettier,prettier/prettier,azz/prettier,Skywalker13/prettier-space-parenthesis,azz/prettier,lydell/prettier,azz/prettier,Skywalker13/prettier-space-parenthesis,existentialism/prettier,existentialism/prettier,arijs/prettier-with-tabs,azz/prettier,rattrayalex/prettier,arijs/prettier-miscellaneous,lydell/prettier,arijs/prettier-miscellaneous,arijs/prettier-with-tabs,Skywalker13/prettier-space-parenthesis,lydell/prettier,prettier/prettier,arijs/prettier-miscellaneous,prettier/prettier,rattrayalex/prettier,existentialism/prettier,lydell/prettier,rattrayalex/prettier,existentialism/prettier,prettier/prettier,arijs/prettier-miscellaneous