code: public static function findBreakingChanges(Schema $oldSchema, Schema $newSchema)
      {
          return array_merge(
              self::findRemovedTypes($oldSchema, $newSchema),
              self::findTypesThatChangedKind($oldSchema, $newSchema),
              self::findFieldsThatChangedTypeOnObjectOrInterfaceTypes($oldSchema, $newSchema),
              self::findFieldsThatChangedTypeOnInputObjectTypes($oldSchema, $newSchema)['breakingChanges'],
              self::findTypesRemovedFromUnions($oldSchema, $newSchema),
              self::findValuesRemovedFromEnums($oldSchema, $newSchema),
              self::findArgChanges($oldSchema, $newSchema)['breakingChanges'],
              self::findInterfacesRemovedFromObjectTypes($oldSchema, $newSchema),
              self::findRemovedDirectives($oldSchema, $newSchema),
              self::findRemovedDirectiveArgs($oldSchema, $newSchema),
              self::findAddedNonNullDirectiveArgs($oldSchema, $newSchema),
              self::findRemovedDirectiveLocations($oldSchema, $newSchema)
          );
      }
docs: Given two schemas, returns an Array containing descriptions of all the types
  of breaking changes covered by the other functions down below.
  
  @return string[][]