Apply suggestions from code review

Co-authored-by: Andrew Murray <3112309+radarhere@users.noreply.github.com>

Author: wiredfool

src/_imagingft.c

@@ -943,6 +943,7 @@ font_render(FontObject *self, PyObject *args) {
     PyObject *imagePtr = PyObject_GetAttrString(image, "ptr");
     if (!imagePtr) {
         PyMem_Del(glyph_info);
+        Py_DECREF(image);
         return NULL;
     }
     im = (Imaging)PyCapsule_GetPointer(imagePtr, IMAGING_MAGIC);

src/_imagingmorph.c

@@ -189,7 +189,7 @@ match(PyObject *self, PyObject *args) {
             if (lut[lut_idx]) {
                 PyObject *coordObj = Py_BuildValue("(nn)", col_idx, row_idx);
                 if (!coordObj) {
-                    Py_XDECREF(ret);
+                    Py_DECREF(ret);
                     return NULL;
                 }
                 PyList_Append(ret, coordObj);
@@ -238,7 +238,7 @@ get_on_pixels(PyObject *self, PyObject *args) {
             if (row[col_idx]) {
                 PyObject *coordObj = Py_BuildValue("(nn)", col_idx, row_idx);
                 if (!coordObj) {
-                    Py_XDECREF(ret);
+                    Py_DECREF(ret);
                     return NULL;
                 }
                 PyList_Append(ret, coordObj);