Revert "fix append-path and vocab-dir to use path-separator"

This reverts commit 0f3026b871.

core/io/pathnames/pathnames.factor

@@ -103,7 +103,7 @@ PRIVATE>
         ] }
         [
             [ trim-tail-separators ]
-            [ trim-head-separators ] bi* path-separator glue
+            [ trim-head-separators ] bi* "/" glue
         ]
     } cond ;
 

core/vocabs/loader/loader.factor

@@ -35,9 +35,7 @@ M: string vocab-path ( string -- path/f )
 PRIVATE>
 
 : vocab-dir ( vocab -- dir )
-    vocab-name
-    os windows? { { CHAR: . CHAR: \\ } } { { CHAR: . CHAR: / } } ?
-    substitute ;
+    vocab-name { { CHAR: . CHAR: / } } substitute ;
 
 : vocab-dir+ ( vocab str/f -- path )
     [ vocab-name "." split ] dip