Elasticsearch indexing does not include the numeric code only

[lvbrobinhood]

Describe the bug

Elasticsearch indexing currently allows for fuzzy matching, but does not match the numeric code only. E.g. for module ST2334, Elasticsearch matches for "S2334" and "T2334", but fails to match for "2334".

To Reproduce

Steps to reproduce the behavior:

1. Go to /courses
2. In the search box, type "2334".
3. You will see "No results found for 2334."

Expected behavior

I suggest an improvement to allow Elasticsearch to index by the numeric code as well.

Additional context

This may require reindexing modules_v2 after the fix in order for Elasticsearch to update its indexing.