Add search filtering by programming language.

Problem to solve

Currently in GitLab there is no ability to filter searches by the programming language they are in.

Further details

When searching in a large project (esp. translated projects) a string can be repeated hundreds of times in translation files when you are simply looking for the original usage in code.

Also, when searching for a particular function call that is popular across many languages it helps narrow the search if you know you only are looking for examples in Javascript.

Adding this feature would greatly improve the usability of GitLab as an online source viewer/browser.

Proposal

Add a programming language filter to searches on GitLab.

What does success look like, and how can we measure that?

The ability to filter searches by programming language being present.

(If no way to measure success, link to an issue that will implement a way to measure this)

Links / references

GitHub searching only Javascript examples: https://github.com/search?l=JavaScript&q=testing&type=Repositories