Fix #2278 keyboard shortcut for tidy code shows replace

[lindapaiste]

Fixes #2278

Changes:

• Handle the keyboard event for Shift-Ctrl-F using the CodeMirror 'extraKeys' option rather than a keydown event handler. CodeMirror will only execute one action per key (unless the handler returns CodeMirror.Pass) so this prevents the Ctrl-F action from being executed when Shift is pressed.

I have verified that this pull request:

• has no linting errors (npm run lint)
• has no test errors (npm run test)
• is from a uniquely-named feature branch and is up to date with the develop branch.
• is descriptively named and links to an issue number, i.e. Fixes #123

[lindapaiste]

Build is failing due to console-feed getting removed from npm. They are trying to get it back but I don't know when that will happen: samdenty/console-feed#124

[raclim]

This works great for me, thanks for working on this!

We're also keeping track of the missing console-feed package, and will probably hold off on merging/deploying for now until it's resolved!