cspell: Allow esac, the shell keyword

Amp-Thread-ID: https://ampcode.com/threads/T-01a0adcb-1b03-716a-852a-cc3746148488
Co-authored-by: Amp <amp@ampcode.com>

Author: marcleblanc2

cspell-allow-list.txt

@@ -190,6 +190,7 @@ entrycommand
 envsubst
 errgroup
 errorf
+esac
 esbenp
 Eswatini
 etcdctl