Remove obsolete notice about renaming the extracted mod folder

This is no longer required thanks to `mod.conf`.

README.md

@@ -18,9 +18,7 @@ git clone https://github.com/minetest-mods/moreblocks.git
 
 You can also
 [download a ZIP archive](https://github.com/minetest-mods/moreblocks/archive/master.zip)
-of More Blocks. If you do so, you will need to extract the archive then rename
-the resulting folder from `moreblocks-master` to `moreblocks` – this is
-**absolutely** required, as the mod won't work otherwise.
+of More Blocks.
 
 ### Enable the mod