fix(ts): honor explicit per-parser generate/from_json = false

lua/ts.lua

@@ -143,6 +143,17 @@ local function name_from_url(url)
     return (name:gsub("%.git$", ""))
 end
 
+---@generic T
+---@param child T?
+---@param parent T?
+---@return T?
+local function pick(child, parent)
+    if child ~= nil then
+        return child
+    end
+    return parent
+end
+
 ---@param entry string | ow.TS.RepoOpts
 ---@return ow.TS.Repo
 local function normalize(entry)
@@ -163,9 +174,8 @@ local function normalize(entry)
             table.insert(parsers, {
                 lang = s.lang,
                 location = s.location,
-                generate = s.generate ~= nil and s.generate or opts.generate,
-                from_json = s.from_json ~= nil and s.from_json
-                    or opts.from_json,
+                generate = pick(s.generate, opts.generate),
+                from_json = pick(s.from_json, opts.from_json),
             })
         end
     else