[v3] Update Markdown files to latest spec (#77)

All Markdown files should, from this point on, start with a level one heading.
See exercism/configlet#150 for the rationale behind these changes.

The full specification can be found [here](https://github.com/exercism/docs/blob/main/contributing/standards/markdown.md).

exercises/practice/bob/.meta/description.md

@@ -1,3 +1,5 @@
+# Description
+
 Bob is a lackadaisical teenager. In conversation, his responses are very limited.
 
 Bob answers 'Sure.' if you ask him a question.