main: Fix blacklist dirs check when there is more than one element

highlighters/main/main-highlighter.zsh

@@ -771,7 +771,7 @@ _zsh_highlight_main_highlighter_check_path()
   tmp_path=$tmp_path:a
 
   while [[ $tmp_path != / ]]; do
-    [[ -n "${(M)X_ZSH_HIGHLIGHT_DIRS_BLACKLIST:#$tmp_path}" ]] && return 1
+    [[ -n ${(M)X_ZSH_HIGHLIGHT_DIRS_BLACKLIST:#$tmp_path} ]] && return 1
     tmp_path=$tmp_path:h
   done
 

highlighters/main/test-data/dirs_blacklist.zsh

@@ -30,7 +30,7 @@
 mkdir foo
 touch foo/bar
 BUFFER=": foo/bar $PWD/foo foo/b"
-X_ZSH_HIGHLIGHT_DIRS_BLACKLIST=($PWD/foo)
+X_ZSH_HIGHLIGHT_DIRS_BLACKLIST=($PWD/foo $PWD/bar)
 
 expected_region_highlight=(
   '1 1 builtin' # :