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)

doc/src/sgml/protocol.sgml

@@ -6773,7 +6773,7 @@ Delete
 <listitem>
 <para>
                 Identifies the following TupleData message as a old tuple.
-                This field is is present if the table in which the delete has
+                This field is present if the table in which the delete has
                 happened has REPLICA IDENTITY set to FULL.
 </para>
 </listitem>

doc/src/sgml/spi.sgml

@@ -2686,7 +2686,7 @@ SPIPlanPtr SPI_saveplan(SPIPlanPtr <parameter>plan</parameter>)
 
  <refnamediv>
   <refname>SPI_register_relation</refname>
-  <refpurpose>make a ephemeral named relation available by name in SPI queries</refpurpose>
+  <refpurpose>make an ephemeral named relation available by name in SPI queries</refpurpose>
  </refnamediv>
 
  <refsynopsisdiv>

src/backend/access/transam/multixact.c

@@ -2555,7 +2555,7 @@ SetOffsetVacuumLimit(bool is_startup)
 
 	/*
 	 * 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);
 
@@ -2732,7 +2732,7 @@ 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

@@ -1581,7 +1581,7 @@ 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/commands/explain.c

@@ -3341,7 +3341,7 @@ ExplainPropertyListNested(const char *qlabel, List *data, ExplainState *es)
  * If "numeric" is true, the value is a number (or other value that
  * doesn't need quoting in JSON).
  *
- * If unit is is non-NULL the text format will display it after the value.
+ * If unit is non-NULL the text format will display it after the value.
  *
  * This usually should not be invoked directly, but via one of the datatype
  * specific routines ExplainPropertyText, ExplainPropertyInteger, etc.

src/backend/executor/nodeModifyTable.c

@@ -1347,7 +1347,7 @@ 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/optimizer/plan/planner.c

@@ -6908,8 +6908,8 @@ apply_scanjoin_target_to_paths(PlannerInfo *root,
 							  scanjoin_targets_contain_srfs);
 
 	/*
-	 * If the relation is partitioned, recurseively apply the same changes to
-	 * all partitions and generate new Append paths. Since Append is not
+	 * If the relation is partitioned, recursively apply the same changes to
+	 * all partitions and generate new Append paths.  Since Append is not
 	 * projection-capable, that might save a separate Result node, and it also
 	 * is important for partitionwise aggregate.
 	 */

src/backend/parser/parse_func.c

@@ -2195,7 +2195,7 @@ LookupFuncWithArgs(ObjectType objtype, ObjectWithArgs *func, bool noError)
 			else if (func->args_unspecified)
 				ereport(ERROR,
 						(errcode(ERRCODE_UNDEFINED_FUNCTION),
-						 errmsg("could not find a aggregate named \"%s\"",
+						 errmsg("could not find an aggregate named \"%s\"",
 								NameListToString(func->objname))));
 			else if (argcount == 0)
 				ereport(ERROR,

src/backend/replication/logical/origin.c

@@ -1455,7 +1455,7 @@ 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))