fixed typos

[grabartley]

Description

I noticed some small typos on the Past Committees page so I corrected them :)

Checklist

I confirm that before I submitted this pull request I did the following:

• [x] Confirmed that no other open PRs address this issue.
• [x] Checked out the latest version of the site.
• [x] Ran yarn start and confirmed that there were no issues.
• [x] Annotated my code with the relevant license information (if applicable).