Sync nucleotide-count

[mk-mxp]

• [ ] Run bin/configlet sync -u -e nucleotide-count --yes --docs --filepaths --metadata --tests include (updates the Markdown files and maybe tests.toml)
  • docs: instructions unsynced: nucleotide-count
• [ ] Drop strict types comments from test file and example code (these are useless)
• [ ] Add and sync test meta data to tests (uuid in DocBlocks / #TestDox())
• [ ] Add exercise to bin/auto-sync.txt to keep it in sync (keep the file alphabetically sorted)
• [ ] Decide on adding / adjusting / ordering test cases to match current problem specs

Do not redesign the student's interface or add test cases that would invalidate existing community solutions. These are extra tasks, which should be discussed in advance.