patch 9.0.1302: on a Belgian keyboard CTRL-] does not work

Problem:    On a Belgian keyboard CTRL-] does not work.
Solution:   Translate CTRL-$ into CTRL-]. (closes #11831)
diff --git a/src/misc2.c b/src/misc2.c
index e3602ee..6133a5e 100644
--- a/src/misc2.c
+++ b/src/misc2.c
@@ -1543,7 +1543,7 @@
     int
 may_adjust_key_for_ctrl(int modifiers, int key)
 {
-    if (!(modifiers & MOD_MASK_CTRL))
+    if ((modifiers & MOD_MASK_CTRL) == 0)
 	return key;
 
     if (ASCII_ISALPHA(key))
@@ -1559,6 +1559,13 @@
 	return '^';
     if (key == '-')
 	return '_';
+
+    // On a Belgian keyboard AltGr $ is ']', on other keyboards '$' can only be
+    // obtained with Shift.  Assume that '$' without shift implies a Belgian
+    // keyboard, where CTRL-$ means CTRL-].
+    if (key == '$' && (modifiers & MOD_MASK_SHIFT) == 0)
+	return ']';
+
     return key;
 }