Update output of `git gud test` on the last level if not all levels were marked as complete

[sahansk2]

(base) sahan@sahan-GA-78LMT-USB3:test$ git gud test
Wow! You've complete every level, congratulations!
If you want to keep learning git, why not try contributing to git-gud by forking the project at https://github.com/benthayer/git-gud/
We're always looking for contributions and are more than happy to accept both pull requests and suggestions!
(base) sahan@sahan-GA-78LMT-USB3:test$ git gud levels --all
All levels and skills:

0. Introduction (intro)
├──X 1. Welcome (welcome)
├──  2. Configuring (config)
└──  3. Initialization (init)
1. Basics (basics)
├──  1. Introduction to Commits (committing)
├──  2. Branching in Git (branching)
├──  3. Merging in Git (merging)
└──  4. Introduction to Rebasing (rebasing)
2. Rampup (rampup)
├──  1. Detaching HEAD (detaching)
├──  2. Relative References I: Using (^) (relrefs1)
├──  3. Relative References II: Using (~) (relrefs2)
└──  4. Reversing Changes in Git (reversing)
3. Rework (rework)
├──  1. Cherrypicking (cherrypicking)
└──  2. Interactive Rebase (irebase)
4. Mixed Bag (mixedbag)
└──  1. One Commit (onecommit)
5. Extras (extras)
└──  1. The Octopus Merge (octopus)
6. Rewriting History (rewriting)
└──O 1. An Easy Level (easy)

Load a level with `git gud load`