Make the ability to use keywords in search more obvious

[ShalokShalom]

Hi there :)

I was today tempted to find my issue reports in a specific repo by simply typing my nick into the search bar and get no issue found.

[machour]

Hey you :)

This is currently supported in the app, just like you would do it on github.com. Try searching for author:ShalokShalom

Not sure if we want to provide a specific UI for this, or if we stick to GitHub keywords

[ShalokShalom]

Well, this is completely hidden now

I suggest a blend-in suggestion text, like:

author: in a greyish color and without being really in the search field, just to show whats possible, or provide a link/popup with all the available querys.