Bug 1901992 - doc: fix the link to uuid generation DONTBUILD

Differential Revision: https://phabricator.services.mozilla.com/D215110

xpcom/docs/xpidl.rst

@@ -179,7 +179,7 @@ uuid must be generated when creating the interface. After that, it doesn't need
 to be changed any more.
 
 ``mach gen-uuid``, a cli tool like ``uuidgen``, or an online tool like
-https://mozilla.pettay.fi/mozuuid.html can help generate UUIDs for new
+https://mozilla.pettay.fi/uuidgen.html can help generate UUIDs for new
 interfaces.
 
 ``builtinclass``