Add package update detection on Content tab (#13807)

doc/client_lua_api.md

@@ -672,6 +672,9 @@ Minetest namespace reference
    * If a flag in this table is set to true, the feature is RESTRICTED.
    * Possible flags: `load_client_mods`, `chat_messages`, `read_itemdefs`,
                    `read_nodedefs`, `lookup_nodes`, `read_playerinfo`
+* `minetest.urlencode(str)`: Encodes non-unreserved URI characters by a
+  percent sign followed by two hex digits. See
+  [RFC 3986, section 2.3](https://datatracker.ietf.org/doc/html/rfc3986#section-2.3).
 
 ### Logging
 * `minetest.debug(...)`
@@ -1551,4 +1554,4 @@ Same as `image`, but does not accept a `position`; the position is instead deter
     texture = "image.png",
     --  ^ Uses texture (string)
 }
-```
+```