Fix misc typos.

Oskari Saarenmaa. Backpatch to stable branches where applicable.

src/backend/access/common/heaptuple.c

@@ -808,7 +808,7 @@ heap_modify_tuple(HeapTuple tuple,
 	 * repl information, as appropriate.
 	 *
 	 * NOTE: it's debatable whether to use heap_deform_tuple() here or just
-	 * heap_getattr() only the non-replaced colums.  The latter could win if
+	 * heap_getattr() only the non-replaced columns.  The latter could win if
 	 * there are many replaced columns and few non-replaced ones. However,
 	 * heap_deform_tuple costs only O(N) while the heap_getattr way would cost
 	 * O(N^2) if there are many non-replaced columns, so it seems better to

src/backend/access/gin/ginfast.c

@@ -887,8 +887,8 @@ ginInsertCleanup(GinState *ginstate,
 												 * locking */
 
 			/*
-			 * remove readed pages from pending list, at this point all
-			 * content of readed pages is in regular structure
+			 * remove read pages from pending list, at this point all
+			 * content of read pages is in regular structure
 			 */
 			if (shiftList(index, metabuffer, blkno, stats))
 			{

src/backend/optimizer/path/costsize.c

@@ -873,7 +873,7 @@ cost_tidscan(Path *path, PlannerInfo *root,
 
 	/*
 	 * The TID qual expressions will be computed once, any other baserestrict
-	 * quals once per retrived tuple.
+	 * quals once per retrieved tuple.
 	 */
 	cost_qual_eval(&tid_qual_cost, tidquals, root);