docs: fix filename casing in TypeScript tutorial

[Lavanya N M (Lavanya-N24)]

Summary

The introductory example references tsc HelloWorld.ts, while the rest of the tutorial consistently uses helloworld.ts.

This updates the introductory compile command to use the same filename for consistency throughout the tutorial.

[Copilot]

Pull request overview

This PR fixes a filename casing inconsistency in the TypeScript tutorial so the introductory tsc example matches the rest of the walkthrough, which uses helloworld.ts.

Changes:

• Update the introductory inline compile command from tsc HelloWorld.ts to tsc helloworld.ts for consistency with the file you create later in the tutorial.