fix: disambiguate arrow function type parameters in JSX

[MathiasWP]

In a JSX file, an arrow function's <T> type parameter list is parsed as the start of a JSX element. The trailing comma that disambiguates it was dropped, so generic arrow functions printed with esrap/languages/tsx no longer compile:

// before
const identity = <T,>(value: T): T => value;   →   const identity = <T>(value: T): T => value;
// TS17008: JSX element 'T' has no corresponding closing tag.

// after
const identity = <T,>(value: T): T => value;   →   const identity = <T,>(value: T): T => value;

The comma is only added where the list is actually ambiguous — a second parameter, a constraint or a default already rules JSX out, so <T, U>, <T extends object> and <T = string> are left alone. Modifiers (const, in, out) do not disambiguate, so <const T> gets the comma too.

Two supporting changes:

• ts() takes an internal second argument set by the tsx module, so this only affects JSX output. The public signature is unchanged.
• esrap.test.js printed every sample with tsx(), including the .ts ones — it now picks the module matching the sample's jsxMode, so ts-arrow-function-types keeps printing plain <T>.

[pkg-svelte-dev]

Install the latest version of esrap from 0112377:

pnpm add https://pkg.svelte.dev/esrap/c/0112377125131496165ebf3a4d296bda76b0a841

Open in pkg.svelte.dev: https://pkg.svelte.dev/repos/esrap/pr/155

Note

This PR is from a fork. A maintainer must approve approve each commit before it can be built and installed.

[changeset-bot]

🦋 Changeset detected

Latest commit: 0112377

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
esrap	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[dummdidumm]

Thank you! The fix looks good but the claim that this does not change public API is wrong - it's changing the public default export. I don't know how we can solve this without moving everything into a new file but I'd like to avoid adding a second parameter if possible