GEOSachem restart improperly named in regrid.pl

A user @pcolarco  reported this:
"I’ve checked out the latest main branch of the model and not that in regrid.pl the achem restart is incorrectly named.
 
Please change the name in the perl script from “geosachem_internal_rst” to “achem_internal_rst” going forward. It is correctly labeled in the AGCM.rc templates."