docs(hg): Fix pull docstring link

why: Sphinx warned about duplicate explicit target name "hg update" in Hg.pull docstring.

what:
- reference hg pull manpage instead of update to avoid conflicting target

Author: tony

src/libvcs/cmd/hg.py

@@ -308,7 +308,7 @@ def pull(
     ) -> str:
         """Update working directory.
 
-        Wraps `hg update <https://www.mercurial-scm.org/doc/hg.1.html#pull>`_.
+        Wraps `hg pull <https://www.mercurial-scm.org/doc/hg.1.html#pull>`_.
 
         Examples
         --------