Fix i18n syntax in Donate Modal to include closing tags

[rebecca-shoptaw]

Closes #9297.

Hotfix. Fixes the last two remaining un-closed tags in our messages.pot file, both of which are located in DonateModal.html.

Technical

• Simply changed the placement of the closing quote and parentheses for the relevant strings
• Also searched the messages.pot file for various HTML opening tags (<a, <i>, <em>, <strong>) and confirmed that, aside from these two, each other opening tag was accompanied by a closing tag

Testing

1. Go the Donate Modal section of the messages.pot file
2. Confirm all opening tags are now closed

Screenshot

Stakeholders

@dcapillae

[scottbarnes]

LGTM.