Enhanced Ctrl + L and URL templates for comments, answers and questions

Shortcut Ctrl + L to add links to a comment. Define URL templates to make it easier to insert links to documentation. Shortcut Ctrl + L to remove a link in a comment ([caret>|](link) -> caret>…

<kbd> markup shortcuts

Makes using the <kbd> tag a snap! This is a cross-browser userscript that adds a button and a keyboard shortcut that operate in the same manner as the other SE, editing buttons.