fix: remove leading newline from <pre> contents

[Rich-Harris]

Alternative to #14783. All we need to do, as far as I can tell, is disregard a \n that immediately follows a <pre> tag

Fixes #14767

Before submitting the PR, please make sure you do the following

• It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs
• Prefix your PR title with feat:, fix:, chore:, or docs:.
• This message body should clearly illustrate what problems it solves.
• Ideally, include a test that fails without this PR but passes with it.
• If this PR changes code within packages/svelte/src, add a changeset (npx changeset).

Tests and linting

• Run the tests with pnpm test and lint the project with pnpm lint

[changeset-bot]

🦋 Changeset detected

Latest commit: af3d03e

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

This PR includes changesets to release 1 package

Name	Type
svelte	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

[github-actions]

Playground

pnpm add https://pkg.pr.new/svelte@14922

[Rich-Harris]

preview: https://svelte-dev-git-preview-svelte-14922-svelte.vercel.app/

this is an automated message

[dummdidumm]

This will result in bugs because in order to have a pre starting with a newline you need to have two newlines: https://html.spec.whatwg.org/multipage/syntax.html#element-restrictions

This is similar to textarea, for which we have related logic elsewhere (but not related to this fix).

[paoloricciuti]

This will result in bugs because in order to have a pre starting with a newline you need to have two newlines: https://html.spec.whatwg.org/multipage/syntax.html#element-restrictions

This is similar to textarea, for which we have related logic elsewhere (but not related to this fix).

Isn't this expected (see this comment #14783 (comment))

[dummdidumm]

adjusted the test and fixed the tests (the one that was adjusted in runtime-legacy hinted at this)