* allow global keyboard shortcuts to override all other shortcuts by providing a special field
* rework the global shortcuts taking priority
* replace bool option with options object in KeyboardManager's keydown handler
* update keyboard shortcut documentation to add information about the new priority setting
* add support for priority global keyboard shortcuts to code mirror
* update the feature's docs to point out it was/will be introduced in 5.2.4
* rollback unnecessary change
* add link to "How to" keyboard shortcuts + styles
* add "How to create keyboard shortcuts"
* Update How to create keyboard shortcuts.tid
* Update How to create keyboard shortcuts.tid
* Update How to create keyboard shortcuts.tid
