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/ex_cmds.c b/src/ex_cmds.c
index d9d532c..91a2fa7 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -99,9 +99,9 @@
 	    IObuff[len++] = ' ';
 	IObuff[len++] = '<';
 	if (enc_utf8 && utf_iscomposing(c)
-# ifdef USE_GUI
+#ifdef USE_GUI
 		&& !gui.in_use
-# endif
+#endif
 		)
 	    IObuff[len++] = ' '; // draw composing char on top of a space
 	len += (*mb_char2bytes)(c, IObuff + len);