Add Web IDE shortcuts to docs and modal

Web IDE shortcuts should be listed with all the other GitLab keyboard shortcuts, including docs (https://docs.gitlab.com/ee/workflow/shortcuts.html) and the cheatsheet modal (?).

The following shortcuts should be documented:

• Cmd-p, Ctrl-p, t - fuzzy file finder

Links / references

https://docs.gitlab.com/ee/workflow/shortcuts.html