bookmarks: rename arguments/variables for source code readability

Before this patch, the argument bound to the source repository of
incoming bookmarks for "bookmarks.diff()" is named as "remote".

But in "hg outgoing" case, this argument is bound to local repository
object.

In addition to it, "local"/"remote" seem to mean not the direction of
propagation of bookmarks, but just the location of cooperative
repositories.

To indicate the direction of propagation of bookmarks clearly on the
source code, this patch uses "d(st)" and "s(rc)" combination instead
of "l(ocal)" and "r(emote)" one.

  - "repo" and "remote" arguments are renamed to "dst" and "src"
  - "lmarks" and "rmarks" variables are renamed to "dmarsk" and "smarks"

mercurial/bookmarks.py

@@ -237,15 +237,15 b' def updatefromremote(ui, repo, remote, p'
     if changed:
         write(repo)
 
-def diff(ui, repo, remote):
+def diff(ui, dst, src):
     ui.status(_("searching for changed bookmarks\n"))
 
-    lmarks = repo.listkeys('bookmarks')
-    rmarks = remote.listkeys('bookmarks')
+    smarks = src.listkeys('bookmarks')
+    dmarks = dst.listkeys('bookmarks')
 
-    diff = sorted(set(rmarks) - set(lmarks))
+    diff = sorted(set(smarks) - set(dmarks))
     for k in diff:
-        mark = ui.debugflag and rmarks[k] or rmarks[k][:12]
+        mark = ui.debugflag and smarks[k] or smarks[k][:12]
         ui.write("   %-25s %s\n" % (k, mark))
 
     if len(diff) <= 0: