Linter: Fix erb-no-trailing-whitespace autofix inside HTML tags

[marcoroth]

This pull request updates erb-no-trailing-whitespace so its autofix also applies to trailing whitespace inside HTML tags, which it previously reported but could never fix.

The rule flags trailing whitespace anywhere in the source, but the autofix only knew how to rewrite HTMLTextNode and LiteralNode content.

Whitespace between attributes, after a tag name, or before a tag closing is tracked as a dedicated WhitespaceNode, so findNodeAtPosition returned null for those offenses, they were created without an autofixContext, and autofix() bailed on its first line. The offense was reported as [Correctable] and counted in N autocorrectable using --fix, but running --fix changed nothing and printed the same line again.

<div     data-a="foo" 
                   data-b="bar">
        lorem
        </div>

Everything inside tag markup was affected, while text content and attribute values already worked:

Related #1697 and #1909, which is the same class of misleading [Correctable] reporting for offenses --fix will not apply.

[github-actions]

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_{🌱 Grown from commit b566eed}

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✅ Preview deployment has been cleaned up.

[pkg-pr-new]

npx https://pkg.pr.new/@herb-tools/formatter@2016

npx https://pkg.pr.new/@herb-tools/language-server@2016

npx https://pkg.pr.new/@herb-tools/linter@2016

commit: b566eed