Add the ability to append definitions, to avoid overwriting other distinct valid definitions

[bengolder]

If an acronym has more than one use, we currently have to be careful about overwriting preexisting definitions. What if we could just append another one?

/gloss TA

ta
Thanks, pronounced "taah" or "tar", depending on where you're from in the UK.

/gloss TA += TA: Technical Assistance

ta
Thanks, pronounced "taah" or "tar", depending on where you're from in the UK.
TA
Technical Assistance

[tmaybe]

See also #27

This is a less complicated way of doing it though.

[bengolder]

ohhhhh. I didn't see that one, sorry. Let me know if you'd like me to move comments to that issue.