Fix various typos and spelling mistakes in code comments

Author: Justin Pryzby
Discussion: https://postgr.es/m/20220411020336.GB26620@telsasoft.com

src/backend/access/brin/brin_minmax_multi.c

@@ -310,7 +310,7 @@ AssertCheckRanges(Ranges *ranges, FmgrInfo *cmpFn, Oid colloid)
 	 */
 	AssertArrayOrder(cmpFn, colloid, ranges->values, 2 * ranges->nranges);
 
-	/* then the single-point ranges (with nvalues boundar values ) */
+	/* then the single-point ranges (with nvalues boundary values ) */
 	AssertArrayOrder(cmpFn, colloid, &ranges->values[2 * ranges->nranges],
 					 ranges->nsorted);
 

src/backend/access/heap/heapam.c

@@ -1470,7 +1470,7 @@ heap_getnextslot_tidrange(TableScanDesc sscan, ScanDirection direction,
 		 * heap_set_tidrange will have used heap_setscanlimits to limit the
 		 * range of pages we scan to only ones that can contain the TID range
 		 * we're scanning for.  Here we must filter out any tuples from these
-		 * pages that are outwith that range.
+		 * pages that are outside of that range.
 		 */
 		if (ItemPointerCompare(&scan->rs_ctup.t_self, mintid) < 0)
 		{

src/backend/access/transam/xlogreader.c

@@ -300,7 +300,7 @@ XLogReleasePreviousRecord(XLogReaderState *state)
 	/* Release the space. */
 	if (unlikely(record->oversized))
 	{
-		/* It's not in the the decode buffer, so free it to release space. */
+		/* It's not in the decode buffer, so free it to release space. */
 		pfree(record);
 	}
 	else

src/backend/access/transam/xlogrecovery.c

@@ -2975,7 +2975,7 @@ ReadRecord(XLogPrefetcher *xlogprefetcher, int emode,
 			/*
 			 * When not in standby mode we find that WAL ends in an incomplete
 			 * record, keep track of that record.  After recovery is done,
-			 * we'll write a record to indicate downstream WAL readers that
+			 * we'll write a record to indicate to downstream WAL readers that
 			 * that portion is to be ignored.
 			 */
 			if (!StandbyMode &&