Fix capitalization of TryAL.dev in README

[Drakonian]

Corrected the capitalization of 'TryAL.dev' to 'tryal.dev' in the README.

What does this PR add or change?

Checklist

• npm run lint passes locally (CI runs it too)
• The task compiles — CI runs npm run compile with the real AL compiler; run it locally to check before pushing (see CONTRIBUTING)
• No solution/ in the PR — this catalog is public; reference solutions are kept privately (see CONTRIBUTING → Reference solutions)
• The task directory name equals metadata.yaml → id
• Everything task.md promises is enforced by a test; good-practice extras are labelled "not graded"
• Objects are referenced by name, never by literal ID
• Hints are ordered gentle → explicit and don't paste the full solution