more adjustments to the c:x;r;a keystroke

The goal is to better handle situations like this one:

╔═══╗
║ - ║
╚═══╝

where the hyphen should not change.

original commit: a0f910c3dcf6ad40971257e9a4bd1b9ca94d3435

collects/framework/private/dir-chars.rkt

@@ -26,19 +26,19 @@
     #\╩ #\╦ #\╣
     #\╝ #\╗ 
     #\═ 
-    #\+ #\-))
+    #\+ #\- #\=))
 
 (define rt-chars
   '(#\╬ 
     #\╩ #\╦ #\╠
     #\╔ #\╚
     #\═
-    #\+ #\-))
+    #\+ #\- #\=))
 
 (define adjustable-chars
   (remove-duplicates
    (append up-chars dn-chars lt-chars rt-chars)))
 
 (define double-barred-chars
-  (remove* '(#\+ #\- #\|) 
+  (remove* '(#\+ #\- #\= #\|) 
            adjustable-chars))