Rename function for consistency

Avoid using prefix "staext" when everything else uses "statext".

Author: Kyotaro HORIGUCHI
Discussion: https://postgr.es/m/20170615.140041.165731947.horiguchi.kyotaro@lab.ntt.co.jp

Author: alvherre

src/backend/statistics/dependencies.c

@@ -633,11 +633,11 @@ dependency_implies_attribute(MVDependency *dependency, AttrNumber attnum)
 }
 
 /*
- * staext_dependencies_load
+ * statext_dependencies_load
  *		Load the functional dependencies for the indicated pg_statistic_ext tuple
  */
 MVDependencies *
-staext_dependencies_load(Oid mvoid)
+statext_dependencies_load(Oid mvoid)
 {
 	bool		isnull;
 	Datum		deps;
@@ -987,7 +987,7 @@ dependencies_clauselist_selectivity(PlannerInfo *root,
 	}
 
 	/* load the dependency items stored in the statistics object */
-	dependencies = staext_dependencies_load(stat->statOid);
+	dependencies = statext_dependencies_load(stat->statOid);
 
 	/*
 	 * Apply the dependencies recursively, starting with the widest/strongest

src/include/statistics/statistics.h

@@ -78,7 +78,7 @@ typedef struct MVDependencies
 #define SizeOfDependencies	(offsetof(MVDependencies, ndeps) + sizeof(uint32))
 
 extern MVNDistinct *statext_ndistinct_load(Oid mvoid);
-extern MVDependencies *staext_dependencies_load(Oid mvoid);
+extern MVDependencies *statext_dependencies_load(Oid mvoid);
 
 extern void BuildRelationExtStatistics(Relation onerel, double totalrows,
 						   int numrows, HeapTuple *rows,