help: remove now-redundant pointer to revsets help

"hg help revisions" and "hg help revsets" now point to the same text,
so drop the revsets reference.

mercurial/commands.py

@@ -3370,8 +3370,7 b' def graft(ui, repo, *revs, **opts):'
 
           hg log -r "sort(all(), date)"
 
-    See :hg:`help revisions` and :hg:`help revsets` for more about
-    specifying revisions.
+    See :hg:`help revisions` for more about specifying revisions.
 
     Returns 0 on successful completion.
     '''
@@ -4580,8 +4579,8 b' def log(ui, repo, *pats, **opts):'
 
     See :hg:`help dates` for a list of formats valid for -d/--date.
 
-    See :hg:`help revisions` and :hg:`help revsets` for more about
-    specifying and ordering revisions.
+    See :hg:`help revisions` for more about specifying and ordering
+    revisions.
 
     See :hg:`help templates` for more about pre-packaged styles and
     specifying custom templates.