devel: fix a typo in a deprecation warning

Credit goes to Sean Farley for spotting it.

mercurial/revset.py

@@ -333,7 +333,7 def getset(repo, subset, x):
     # else case should not happen, because all non-func are internal,
     # ignoring for now.
     if x[0] == 'func' and x[1][0] == 'symbol' and x[1][1] in symbols:
-        repo.ui.deprecwarn('revset "%s" use list instead of smartset'
+        repo.ui.deprecwarn('revset "%s" uses list instead of smartset'
                            % x[1][1],
                            '3.9')
     return baseset(s)

tests/test-devel-warnings.t

@@ -122,7 +122,7
   [255]
 
   $ hg log -r "oldstyle()" -T '{rev}\n'
-  devel-warn: revset "oldstyle" use list instead of smartset
+  devel-warn: revset "oldstyle" uses list instead of smartset
   (compatibility will be dropped after Mercurial-3.9, update your code.) at: *mercurial/revset.py:* (mfunc) (glob)
   0
   $ hg oldanddeprecated
@@ -144,7 +144,7
    */mercurial/util.py:* in check (glob)
    $TESTTMP/buggylocking.py:* in oldanddeprecated (glob)
   $ hg blackbox -l 9
-  1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> devel-warn: revset "oldstyle" use list instead of smartset
+  1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> devel-warn: revset "oldstyle" uses list instead of smartset
   (compatibility will be dropped after Mercurial-3.9, update your code.) at: *mercurial/revset.py:* (mfunc) (glob)
   1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> log -r oldstyle() -T {rev}\n exited 0 after * seconds (glob)
   1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> oldanddeprecated