Fix typos and duplicate words

This fixes various typos, duplicated words, and tiny bits of whitespace
mainly in code comments but also in docs.

Author: Daniel Gustafsson <daniel@yesql.se>
Author: Heikki Linnakangas <hlinnaka@iki.fi>
Author: Alexander Lakhin <exclusion@gmail.com>
Author: David Rowley <dgrowleyml@gmail.com>
Author: Nazir Bilal Yavuz <byavuz81@gmail.com>
Discussion: https://postgr.es/m/3F577953-A29E-4722-98AD-2DA9EFF2CBB8@yesql.se

src/backend/utils/adt/jsonpath_exec.c

@@ -4221,7 +4221,7 @@ JsonTableSetDocument(TableFuncScanState *state, Datum value)
 }
 
 /*
- * Evaluate a JsonTablePlan's jsonpath to get a new row pattren from
+ * Evaluate a JsonTablePlan's jsonpath to get a new row pattern from
  * the given context item
  */
 static void
@@ -4339,7 +4339,7 @@ JsonTablePlanScanNextRow(JsonTablePlanState *planstate)
 		/*
 		 * Now fetch the nested plan's current row to be joined against the
 		 * parent row.  Any further nested plans' paths will be re-evaluated
-		 * reursively, level at a time, after setting each nested plan's
+		 * recursively, level at a time, after setting each nested plan's
 		 * current row.
 		 */
 		(void) JsonTablePlanNextRow(planstate->nested);

src/backend/utils/adt/multirangetypes.c

@@ -330,7 +330,7 @@ multirange_out(PG_FUNCTION_ARGS)
 }
 
 /*
- * Binary representation: First a int32-sized count of ranges, followed by
+ * Binary representation: First an int32-sized count of ranges, followed by
  * ranges in their native binary representation.
  */
 Datum

src/backend/utils/adt/selfuncs.c

@@ -6968,7 +6968,7 @@ btcostestimate(PlannerInfo *root, IndexPath *path, double loop_count,
 		 * btree scans, making the top-level scan look like a continuous scan
 		 * (as opposed to num_sa_scans-many primitive index scans).  After
 		 * all, btree scans mostly work like that at runtime.  However, such a
-		 * scheme would badly bias genericcostestimate's simplistic appraoch
+		 * scheme would badly bias genericcostestimate's simplistic approach
 		 * to calculating numIndexPages through prorating.
 		 *
 		 * Stick with the approach taken by non-native SAOP scans for now.

src/backend/utils/mmgr/aset.c

@@ -979,8 +979,8 @@ AllocSetAlloc(MemoryContext context, Size size, int flags)
 	Assert(set->blocks != NULL);
 
 	/*
-	 * If requested size exceeds maximum for chunks we hand the the request
-	 * off to AllocSetAllocLarge().
+	 * If requested size exceeds maximum for chunks we hand the request off to
+	 * AllocSetAllocLarge().
 	 */
 	if (size > set->allocChunkLimit)
 		return AllocSetAllocLarge(context, size, flags);

src/backend/utils/mmgr/bump.c

@@ -505,8 +505,8 @@ BumpAlloc(MemoryContext context, Size size, int flags)
 #endif
 
 	/*
-	 * If requested size exceeds maximum for chunks we hand the the request
-	 * off to BumpAllocLarge().
+	 * If requested size exceeds maximum for chunks we hand the request off to
+	 * BumpAllocLarge().
 	 */
 	if (chunk_size > set->allocChunkLimit)
 		return BumpAllocLarge(context, size, flags);

src/backend/utils/mmgr/generation.c

@@ -541,8 +541,8 @@ GenerationAlloc(MemoryContext context, Size size, int flags)
 #endif
 
 	/*
-	 * If requested size exceeds maximum for chunks we hand the the request
-	 * off to GenerationAllocLarge().
+	 * If requested size exceeds maximum for chunks we hand the request off to
+	 * GenerationAllocLarge().
 	 */
 	if (chunk_size > set->allocChunkLimit)
 		return GenerationAllocLarge(context, size, flags);