Minimize when CSS Code Hints are Popped Up

Old Title: DO NOT MERGE: CSS Code Hints test branch

To help everyone test when best to popup CSS Code Hints for Properties, I add some menu commands to toggle settings to make it easy to play with.

Currently, CSS Code Hints for Properties popup on 3 different actions:

1. If you type a separator { or ;

Note that { is disabled in master and sprint 19 due to a conflict with German keyboard, but I re-enabled it in this branch

2. When you type whitespace (space, tab, or newline)

3. when you start typing a property name

I added temporary toggles to the Debug menu in this branch to allow turning off cases 1 and 2 above.

Please test this out and let us know what you think. Some thing to test:
a. typing in a new rule from scratch
b. editing an existing rule

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UPDATE: I changed it to only Case 3.

This fixes #2627