queries: fixup highlight tests

test/highlight/connection.d2

@@ -22,11 +22,11 @@ a <---> b
 # ^ operator
 
 a.b.c --> d.e
-# <- constant
+# <- string.special
-# ^ constant
+# ^ string.special
 #   ^ variable
 #     ^ operator
-#         ^ constant
+#         ^ string.special
 #           ^ variable
 
 

test/highlight/grid.d2

@@ -25,7 +25,7 @@ header
 # <- variable
 
 body: "" {
-  # <- constant
+  # <- string.special
   # ^ punctuation.delimiter
   #   ^ string
   #      ^ punctuation.bracket

test/highlight/shape.d2

@@ -1,5 +1,5 @@
 foo.'baz'.biz
-# <- constant
+# <- string.special
 #  ^ punctuation.delimiter
 #   ^ string
 #     ^ string
@@ -26,12 +26,12 @@ foo: Foo Bar
 #    ^ text.title
 
 foo: Foo Bar {
-  # <- constant
+  # <- string.special
   #  ^ text.title
   #          ^ punctuation.bracket
 
   bar.baz
-  # <- constant
+  # <- string.special
   #   ^ variable
 }
 # <- punctuation.bracket