Rename "Last commit" to "Last updated"

Last commit is confusing because it's actually the `updated_at` of the
repository. By renaming it, this will be clearer to users.

extensions/ql-vscode/docs/test-plan.md

@@ -244,7 +244,7 @@ This requires running a MRVA query and seeing the results view.
    1. By name 
    2. By results 
    3. By stars 
-   4. By last commit
+   4. By last updated
 9. Can filter repos
 10. Shows correct statistics 
     1. Total number of results 

extensions/ql-vscode/src/view/variant-analysis/RepositoriesSort.tsx

@@ -32,7 +32,7 @@ export const RepositoriesSort = ({ value, onChange, className }: Props) => {
       <VSCodeOption value={SortKey.Name}>Name</VSCodeOption>
       <VSCodeOption value={SortKey.ResultsCount}>Results</VSCodeOption>
       <VSCodeOption value={SortKey.Stars}>Stars</VSCodeOption>
-      <VSCodeOption value={SortKey.LastUpdated}>Last commit</VSCodeOption>
+      <VSCodeOption value={SortKey.LastUpdated}>Last updated</VSCodeOption>
     </Dropdown>
   );
 };