CLEANUP: Fix spelling errors in comments

This is from the output of codespell. It's done at once over a bunch
of files and only affects comments, so there is nothing user-visible.
No backport needed.
diff --git a/src/proxy.c b/src/proxy.c
index a47c2f6..8b2cf4f 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -421,7 +421,7 @@
 		return -1;
 	}
 
-	/* Capture keywork is only available in frontend. */
+	/* Capture keyword is only available in frontend. */
 	if (!(curpx->cap & PR_CAP_FE)) {
 		memprintf(err, "'%s' only available in frontend or listen section", args[0]);
 		return -1;