Fix typos in decode.c and logical.c.

Per report by Ajin Cherian in email:
https://postgr.es/m/CAFPTHDYnRKDvzgDxoMn_CKqXA-D0MtrbyJvfvjBsO4G=UHDXkg@mail.gmail.com

src/backend/replication/logical/decode.c

@@ -685,10 +685,10 @@ DecodeCommit(LogicalDecodingContext *ctx, XLogRecordBuffer *buf,
 	 * so during startup, to get to the first transaction the client needs. As
 	 * we have reset the catalog caches before starting to read WAL, and we
 	 * haven't yet touched any catalogs, there can't be anything to invalidate.
-	 * But if we're "forgetting" this commit because it's it happened in
-	 * another database, the invalidations might be important, because they
-	 * could be for shared catalogs and we might have loaded data into the
-	 * relevant syscaches.
+	 * But if we're "forgetting" this commit because it happened in another
+	 * database, the invalidations might be important, because they could be
+	 * for shared catalogs and we might have loaded data into the relevant
+	 * syscaches.
 	 * ---
 	 */
 	if (DecodeTXNNeedSkip(ctx, buf, parsed->dbId, origin_id))

src/backend/replication/logical/logical.c

@@ -1371,7 +1371,7 @@ stream_commit_cb_wrapper(ReorderBuffer *cache, ReorderBufferTXN *txn,
 	ctx->write_xid = txn->xid;
 	ctx->write_location = txn->end_lsn;
 
-	/* in streaming mode, stream_abort_cb is required */
+	/* in streaming mode, stream_commit_cb is required */
 	if (ctx->callbacks.stream_commit_cb == NULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),