treesitter: add predicate "any-of?" (#14344)

For the case of Clojure and other Lisp syntax highlighting, it is
necessary to create huge regexps consisting of hundreds of symbols with
the pipe (|) character. To make things more difficult, these Lisp
symbols sometimes consists of special characters that are themselves
part of special regexp characters like '*'. In addition to being
difficult to maintain, it's performance is suboptimal.

This patch introduces a new predicate to perform 'source' matching in
amortized constant time. This is accomplished by compiling a hash table
on the first use.

runtime/lua/vim/treesitter/query.lua

@@ -260,7 +260,25 @@ local predicate_handlers = {
     end
 
     return false
-  end
+  end,
+
+  ["any-of?"] = function(match, _, source, predicate)
+    local node = match[predicate[2]]
+    local node_text = M.get_node_text(node, source)
+
+    -- Since 'predicate' will not be used by callers of this function, use it
+    -- to store a string set built from the list of words to check against.
+    local string_set = predicate["string_set"]
+    if not string_set then
+      string_set = {}
+      for i=3,#predicate do
+        string_set[predicate[i]] = true
+      end
+      predicate["string_set"] = string_set
+    end
+
+    return string_set[node_text]
+  end,
 }
 
 -- As we provide lua-match? also expose vim-match?