patch 8.2.0830: Motif: can't map "!"

Problem:    Motif: can't map "!". (Ben Jackson)
Solution:   Remove the shift modifier if it's already included in the key.
            (closes #6147)

src/gui_x11.c

@@ -948,6 +948,11 @@ gui_x11_key_hit_cb(
     {
 	string[0] = key;
 	len = 1;
+
+	// Remove the SHIFT modifier for keys where it's already included,
+	// e.g., '(', '!' and '*'.
+	if (!ASCII_ISALPHA(key) && key > 0x20 && key < 0x7f)
+	    modifiers &= ~MOD_MASK_SHIFT;
     }
 
     if (modifiers != 0)

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    830,
 /**/
     829,
 /**/