Adds title attributes to extension buttons

[jonathansampson]

Test Plan:

With a screen reader enabled:

1. Place focus on address bar
2. Press tab until extension buttons are encountered
3. Listen for extension name to be mentioned

PR Details:

• 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).

Resolves #8269

[bsclifton]

Works as expected! Good catch- this is a nice touch 😄

(btw- I only tested using mouse hover, rather than with screen reader)

[cezaraugusto]

++ great