shelve: move mutableancestors to not be a closure

There's no value in it being a closure and everyone who tries to read
the outer function code will be distracted by it. IMO moving it out
significantly improves readability, especially given how clear it is
what mutableancestors function does from its name.

hgext/shelve.py

@@ -273,24 +273,24 b' def getshelvename(repo, parent, opts):'
         raise error.Abort(_("shelved change names may not start with '.'"))
     return name
 
-def _docreatecmd(ui, repo, pats, opts):
-    def mutableancestors(ctx):
-        """return all mutable ancestors for ctx (included)
+def mutableancestors(ctx):
+    """return all mutable ancestors for ctx (included)
 
-        Much faster than the revset ancestors(ctx) & draft()"""
-        seen = set([nodemod.nullrev])
-        visit = collections.deque()
-        visit.append(ctx)
-        while visit:
-            ctx = visit.popleft()
-            yield ctx.node()
-            for parent in ctx.parents():
-                rev = parent.rev()
-                if rev not in seen:
-                    seen.add(rev)
-                    if parent.mutable():
-                        visit.append(parent)
+    Much faster than the revset ancestors(ctx) & draft()"""
+    seen = set([nodemod.nullrev])
+    visit = collections.deque()
+    visit.append(ctx)
+    while visit:
+        ctx = visit.popleft()
+        yield ctx.node()
+        for parent in ctx.parents():
+            rev = parent.rev()
+            if rev not in seen:
+                seen.add(rev)
+                if parent.mutable():
+                    visit.append(parent)
 
+def _docreatecmd(ui, repo, pats, opts):
     wctx = repo[None]
     parents = wctx.parents()
     if len(parents) > 1: