Fix various documentation, user-facing, and source comment typos (#16367)

* Fix various doc, user-facing, and source comment typos

Found via `codespell -q 3 -S ./options/locale,./vendor -L ba,pullrequest,pullrequests,readby`

modules/validation/refname_test.go

@@ -12,7 +12,7 @@ import (
 
 var gitRefNameValidationTestCases = []validationTestCase{
 	{
-		description: "Referece contains only characters",
+		description: "Reference name contains only characters",
 		data: TestForm{
 			BranchName: "test",
 		},