Update chuck_norris.lua

I missed an open bracket in my PR and resulting this plugin not working as expectedly.
I added back unescape function which already fixed.
you can test the plugin on my bot ```@botix```

plugins/chuck_norris.lua

@@ -1,20 +1,36 @@
-local function chuck()
-  local random = http.request("http://api.icndb.com/jokes/random")
-  local decode = json:decode(random)
-  local joke = decode.value.joke
-  return joke
-end
+do
 
-local function run(msg)
-  local joke = chuck()
-  return unescape_html(joke)
-end
+  local function unescape(str)
+    str = string.gsub( str, '&lt;', '<' )
+    str = string.gsub( str, '&gt;', '>' )
+    str = string.gsub( str, '&quot;', '"' )
+    str = string.gsub( str, '&apos;', "'" )
+    str = string.gsub( str, '&#(%d+);', function(n) return string.char(n) end )
+    str = string.gsub( str, '&#x(%d+);', function(n) return string.char(tonumber(n,16)) end )
+    str = string.gsub( str, '&amp;', '&' ) -- Be sure to do this after all others
+  return str
+  end
+
+  local function chuck()
+    local random = http.request("http://api.icndb.com/jokes/random")
+    local decode = json:decode(random)
+    local joke = decode.value.joke
+    local unescape = unescape(joke)
+    return unescape
+  end
 
-return {
-  description = "Get random Chuck Norris jokes.", 
-  usage = "!chuck",
-  patterns = {
-    "^!chuck$"
+  function run(msg)
+    local joke = chuck()
+    return joke
+  end
+
+  return {
+    description = "Get random Chuck Norris jokes.", 
+    usage = "!chuck",
+    patterns = {
+      "^!chuck$"
   }, 
   run = run
-}
+}
+
+end