(Fget_text_property): Simplify using Ftext_properties_at.

src/textprop.c

@@ -501,25 +501,9 @@ OBJECT is optional and defaults to the current buffer.\n\
 If POSITION is at the end of OBJECT, the value is nil.")
   (pos, prop, object)
      Lisp_Object pos, object;
-     register Lisp_Object prop;
+     Lisp_Object prop;
 {
-  register INTERVAL i;
-  register Lisp_Object tail;
-
-  if (NILP (object))
-    XSET (object, Lisp_Buffer, current_buffer);
-  i = validate_interval_range (object, &pos, &pos, soft);
-  if (NULL_INTERVAL_P (i))
-    return Qnil;
-
-  /* If POS is at the end of the interval,
-     it means it's the end of OBJECT.
-     There are no properties at the very end,
-     since no character follows.  */
-  if (XINT (pos) == LENGTH (i) + i->position)
-    return Qnil;
-
-  return textget (i->plist, prop);
+  return textget (Ftext_properties_at (pos, object), prop);
 }
 
 DEFUN ("get-char-property", Fget_char_property, Sget_char_property, 2, 3, 0,