patch 8.2.4288: preprocessor indents are inconsistent

Problem:    Preprocessor indents are inconsistent.
Solution:   Fix preprocessor indents. (Ken Takata, closes #9691)
diff --git a/src/arglist.c b/src/arglist.c
index fbd99af..5c22369 100644
--- a/src/arglist.c
+++ b/src/arglist.c
@@ -969,9 +969,9 @@
     old_curwin = curwin;
     old_curtab = curtab;
 
-# ifdef FEAT_GUI
+#ifdef FEAT_GUI
     need_mouse_correct = TRUE;
-# endif
+#endif
 
     // Try closing all windows that are not in the argument list.
     // Also close windows that are not full width;