patch 9.0.1234: the code style has to be checked manually

Problem:    The code style has to be checked manually.
Solution:   Add basic code style checks in a test.  Fix or avoid uncovered
            problems.
diff --git a/src/gui_beval.c b/src/gui_beval.c
index daeac8f..9d85d90 100644
--- a/src/gui_beval.c
+++ b/src/gui_beval.c
@@ -645,7 +645,8 @@
 
 		XtTranslateKeycode(gui.dpy, event->xkey.keycode,
 				event->xkey.state, &modifier, &keysym);
-		if ((keysym == XK_Shift_L) || (keysym == XK_Shift_R)) {
+		if ((keysym == XK_Shift_L) || (keysym == XK_Shift_R))
+		{
 		    beval->showState = ShS_UPDATE_PENDING;
 		    (*beval->msgCB)(beval, 0);
 		}