Capitalize menu items

[cndouglas]

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).

Test Plan:

1. Open a new window in Brave and open the menu bar, if necessary.
2. Select Bravery on the menubar. Make sure two titles are exactly "Bravery Global Settings…" and "Bravery Site Settings…".
3. Select Help on the menubar. Make sure a title is exactly "Spread the Word About Brave…".
4. Select Edit on the menubar. Make sure a title is exactly "Paste Without Formatting".

Fixes #5377

[bsclifton]

Looks good! Thanks for grabbing this 😄