Add spelling correction for gather and variants.

Author: cfi-gb

codespell_lib/data/dictionary.txt

@@ -29741,6 +29741,10 @@ gatable->gateable
 gateing->gating
 gatherig->gathering
 gatherin->gathering, gather in,
+gathter->gather
+gathtered->gathered
+gathtering->gathering
+gathters->gathers
 gatin->gating, latin, satin, gain, gratin,
 gatway->gateway
 gauage->gauge