Add some entries to dictionary_informal.txt

Author: skangas

codespell_lib/data/dictionary_informal.txt

@@ -1,8 +1,19 @@
+ain't->am not, are not, is not, has not, have not,
+betcha->bet you
+biggie->big deal
+cuppa->cup of
 dunno->don't know
 gimme->give me
 gonna->going to
+gotcha->got you
 gotta->got to
+innit->isn't it, in it,
+kinda->kind of
+lemme->let me
 natch->match
+outta->out of
+sorta->sort of
 tho->though, to, thou,
 thru->through
 wanna->want to
+y'all->you all