[Sublime Text] Enable resetting font size to a predefined default value.

Default (OSX).sublime-keymap

[
  { "keys": ["super+0"], "command": "reset_font_size_to_user_defaults" }
]

Preferences.sublime-settings

{
  "default_font_size": 10
}

reset_font_size_command.py

import sublime
import sublime_plugin


class ResetFontSizeToUserDefaultsCommand(sublime_plugin.ApplicationCommand):
    def run(self):
        s = sublime.load_settings("Preferences.sublime-settings")

        if s.has('default_font_size'):
            s.set('font_size', s.get('default_font_size'))
            sublime.save_settings("Preferences.sublime-settings")