'main': Fix the last commit's issue concerning parameter expansion at command word.

highlighters/main/test-data/path-dollared-word3.zsh

@@ -29,9 +29,11 @@
 
 # «/usr» at this point would be highlighted as path_prefix; so should
 # a parameter that expands to an equivalent string be highlighted.
+#
+# More complicated parameter substitutions aren't eval'd; issue #328.
 BUFFER='$PWD; ${PWD}'
 
 expected_region_highlight=(
-  "1 4 unknown-token" # $PWD - not eval'd; issue #328
+  "1 4 path" # $PWD
   "7 12 unknown-token" # ${PWD}
 )