Fix misc typos, mostly in comments.

A collection of typos I happened to spot while reading code, as well as
grepping for common mistakes.

Backpatch to all supported versions, as applicable, to avoid conflicts
when backporting other commits in the future.

Author: hlinnaka

contrib/bloom/blscan.c

@@ -76,7 +76,7 @@ blendscan(IndexScanDesc scan)
 }
 
 /*
- * Insert all matching tuples into to a bitmap.
+ * Insert all matching tuples into a bitmap.
  */
 int64
 blgetbitmap(IndexScanDesc scan, TIDBitmap *tbm)

src/backend/access/transam/multixact.c

@@ -2551,7 +2551,7 @@ SetOffsetVacuumLimit(void)
 
 	/*
 	 * NB: Have to prevent concurrent truncation, we might otherwise try to
-	 * lookup a oldestMulti that's concurrently getting truncated away.
+	 * lookup an oldestMulti that's concurrently getting truncated away.
 	 */
 	LWLockAcquire(MultiXactTruncationLock, LW_SHARED);
 
@@ -2727,7 +2727,7 @@ find_multixact_start(MultiXactId multi, MultiXactOffset *result)
 	/*
 	 * Flush out dirty data, so PhysicalPageExists can work correctly.
 	 * SimpleLruFlush() is a pretty big hammer for that.  Alternatively we
-	 * could add a in-memory version of page exists, but find_multixact_start
+	 * could add an in-memory version of page exists, but find_multixact_start
 	 * is called infrequently, and it doesn't seem bad to flush buffers to
 	 * disk before truncation.
 	 */

src/backend/commands/cluster.c

@@ -1542,7 +1542,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
 	 * swap_relation_files()), thus relfrozenxid was not updated. That's
 	 * annoying because a potential reason for doing a VACUUM FULL is a
 	 * imminent or actual anti-wraparound shutdown.  So, now that we can
-	 * access the new relation using it's indices, update relfrozenxid.
+	 * access the new relation using its indices, update relfrozenxid.
 	 * pg_class doesn't have a toast relation, so we don't need to update the
 	 * corresponding toast relation. Not that there's little point moving all
 	 * relfrozenxid updates here since swap_relation_files() needs to write to

src/backend/executor/nodeModifyTable.c

@@ -1067,7 +1067,7 @@ lreplace:;
  * (but still lock row, even though it may not satisfy estate's
  * snapshot).
  *
- * Returns true if if we're done (with or without an update), or false if
+ * Returns true if we're done (with or without an update), or false if
  * the caller must retry the INSERT from scratch.
  */
 static bool

src/backend/replication/logical/origin.c

@@ -1404,7 +1404,7 @@ pg_show_replication_origin_status(PG_FUNCTION_ARGS)
 	int			i;
 #define REPLICATION_ORIGIN_PROGRESS_COLS 4
 
-	/* we we want to return 0 rows if slot is set to zero */
+	/* we want to return 0 rows if slot is set to zero */
 	replorigin_check_prerequisites(false, true);
 
 	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))

src/bin/initdb/t/001_initdb.pl

@@ -1,4 +1,4 @@
-# To test successful data directory creation with a additional feature, first
+# To test successful data directory creation with an additional feature, first
 # try to elaborate the "successful creation" test instead of adding a test.
 # Successful initdb consumes much time and I/O.
 

src/bin/pg_upgrade/tablespace.c

@@ -36,7 +36,7 @@ init_tablespaces(void)
  * get_tablespace_paths()
  *
  * Scans pg_tablespace and returns a malloc'ed array of all tablespace
- * paths. Its the caller's responsibility to free the array.
+ * paths. It's the caller's responsibility to free the array.
  */
 static void
 get_tablespace_paths(void)

src/interfaces/ecpg/ecpglib/execute.c

@@ -1310,8 +1310,8 @@ ecpg_build_params(struct statement * stmt)
 		if ((position = next_insert(stmt->command, position, stmt->questionmarks, std_strings) + 1) == 0)
 		{
 			/*
-			 * We have an argument but we dont have the matched up placeholder
-			 * in the string
+			 * We have an argument but we don't have the matched up
+			 * placeholder in the string
 			 */
 			ecpg_raise(stmt->lineno, ECPG_TOO_MANY_ARGUMENTS,
 					   ECPG_SQLSTATE_USING_CLAUSE_DOES_NOT_MATCH_PARAMETERS,

src/pl/tcl/pltcl.c

@@ -2523,7 +2523,7 @@ pltcl_SPI_execute_plan(ClientData cdata, Tcl_Interp *interp,
 	}
 
 	/************************************************************
-	 * If there was a argtype list on preparation, we need
+	 * If there was an argtype list on preparation, we need
 	 * an argument value list now
 	 ************************************************************/
 	if (qdesc->nargs > 0)

src/test/regress/expected/rowsecurity.out

@@ -1614,7 +1614,7 @@ SET SESSION AUTHORIZATION regress_rls_bob;
 INSERT INTO document VALUES (79, (SELECT cid from category WHERE cname = 'technology'), 1, 'regress_rls_bob', 'technology book, can only insert')
     ON CONFLICT (did) DO UPDATE SET dtitle = EXCLUDED.dtitle RETURNING *;
 ERROR:  new row violates row-level security policy for table "document"
--- UPDATE path is taken here.  Existing tuple passes, since it's cid
+-- UPDATE path is taken here.  Existing tuple passes, since its cid
 -- corresponds to "novel", but default USING qual is enforced against
 -- post-UPDATE tuple too (as always when updating with a policy that lacks an
 -- explicit WCO), and so this fails: