Update usage.md (#225)

Author: xPaw

_docs/usage.md

@@ -9,6 +9,12 @@ Once The Lounge is installed, a program called `thelounge` is now available.
 
 {% include toc.md %}
 
+## Client help
+
+To view available keybinds, autocompletion options, and commands, press the <svg aria-hidden="true" focusable="false" role="img" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" width="16" height="16"><path fill="currentColor" d="M504 256c0 136.997-111.043 248-248 248S8 392.997 8 256C8 119.083 119.043 8 256 8s248 111.083 248 248zM262.655 90c-54.497 0-89.255 22.957-116.549 63.758-3.536 5.286-2.353 12.415 2.715 16.258l34.699 26.31c5.205 3.947 12.621 3.008 16.665-2.122 17.864-22.658 30.113-35.797 57.303-35.797 20.429 0 45.698 13.148 45.698 32.958 0 14.976-12.363 22.667-32.534 33.976C247.128 238.528 216 254.941 216 296v4c0 6.627 5.373 12 12 12h56c6.627 0 12-5.373 12-12v-1.333c0-28.462 83.186-29.647 83.186-106.667 0-58.002-60.165-102-116.531-102zM256 338c-25.365 0-46 20.635-46 46 0 25.364 20.635 46 46 46s46-20.636 46-46c0-25.365-20.635-46-46-46z"></path></svg> help button in the sidebar next to the settings cog.
+
+This page also checks for The Lounge and package updates, and allows you to read the changelog for the currently installed version.
+
 ## Command line help
 
 To get general information about the program and an overview of the available