remove unnecessary list comprehensions

These result lists were only built for the side effects, and so a
normal loop is just as good and more straight-forward.

mercurial/context.py

@@ -722,7 +722,8 b' class workingctx(changectx):'
 
     def tags(self):
         t = []
-        [t.extend(p.tags()) for p in self.parents()]
+        for p in self.parents():
+            t.extend(p.tags())
         return t
 
     def children(self):

mercurial/ignore.py

@@ -86,7 +86,8 b' def ignore(root, files, warn):'
                      (f, inst.strerror))
 
     allpats = []
-    [allpats.extend(patlist) for patlist in pats.values()]
+    for patlist in pats.values():
+        allpats.extend(patlist)
     if not allpats:
         return util.never
 

mercurial/localrepo.py

@@ -1242,7 +1242,8 b' class localrepository(repo.repository):'
                     self.ui.status(_("skipping missing subrepository: %s\n")
                                    % subpath)
 
-        [l.sort() for l in r]
+        for l in r:
+            l.sort()
         return r
 
     def heads(self, start=None):