Code review comment for lp:~azzar1/unity/shortcut-hint

Looking great! ;-) However there are a few minor issues that need to be fixed before this lands.

The feedback below is based on comparing the implementation screenshot posted with the following designs:
- https://launchpadlibrarian.net/85352653/Super_key_shutcuts_overlay.png (the design itself)
- https://launchpadlibrarian.net/86861725/keyboard_shortcuts_sizes.png (the grid the design is build on)

Items in need of fixing:

1. The divider lines should by 10% opacity (while remaining 100% white)

2. The divider should start flush with text, and end flush with grid (see grid design above)

3. The divider lines should have flat ends

4. The spacing of the title "Keyboard Shortcuts" is slightly out, should have slightly more space above than below (see design)

5. The spacing of the section titles is slightly out, should have slightly more space above each title than below (see design)

6. The shortcuts need updating to exactly match those specified in the following document https://docs.google.com/a/canonical.com/document/d/1jqeKtIJwqLtl58Wk_fqjr9Rrgxn9zsouCYOo-cZsLSE/edit?authkey=CLGG9NkJ&hl=en_GB

Once these are fixed we are good to go, thx!