Replace nearly all XXX0vv comments with smarter ones

So, back long ago, XXX012 meant, "before Tor 0.1.2 is released, we
had better revisit this comment and fix it!"

But we have a huge pile of such comments accumulated for a large
number of released versions!  Not cool.

So, here's what I tried to do:

  * 0.2.9 and 0.2.8 are retained, since those are not yet released.

  * XXX+ or XXX++ or XXX++++ or whatever means, "This one looks
    quite important!"

  * The others, after one-by-one examination, are downgraded to
    plain old XXX.  Which doesn't mean they aren't a problem -- just
    that they cannot possibly be a release-blocking problem.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/or/microdesc.c b/src/or/microdesc.c
index 5b5c29a6d2..f3788f4209 100644
--- a/src/or/microdesc.c
+++ b/src/or/microdesc.c
@@ -925,7 +925,7 @@ we_use_microdescriptors_for_circuits(const or_options_t *options)
       return 0;
     /* Otherwise, we decide that we'll use microdescriptors iff we are
      * not a server, and we're not autofetching everything. */
-    /* XXX023 what does not being a server have to do with it? also there's
+    /* XXXX++ what does not being a server have to do with it? also there's
      * a partitioning issue here where bridges differ from clients. */
     ret = !server_mode(options) && !options->FetchUselessDescriptors;
   }