fix: allow attributes on the title element

The spec states the title element supports global attributes.
https://html.spec.whatwg.org/#the-title-element

Reverts the title attribute validation introduced in sveltejs#1721.

Fixes sveltejs#5198.

Author: jschaf

documentation/docs/98-reference/.generated/compile-errors.md

@@ -1082,12 +1082,6 @@ Expected a valid element or component name. Components must have a valid variabl
 A `<textarea>` can have either a value attribute or (equivalently) child content, but not both
 ```
 
-### title_illegal_attribute
-
-```
-`<title>` cannot have attributes nor directives
-```
-
 ### title_invalid_content
 
 ```

packages/svelte/messages/compile-errors/template.md

@@ -398,10 +398,6 @@ See https://html.spec.whatwg.org/multipage/custom-elements.html#valid-custom-ele
 
 > A `<textarea>` can have either a value attribute or (equivalently) child content, but not both
 
-## title_illegal_attribute
-
-> `<title>` cannot have attributes nor directives
-
 ## title_invalid_content
 
 > `<title>` can only contain text and {tags}

packages/svelte/src/compiler/errors.js

@@ -1573,15 +1573,6 @@ export function textarea_invalid_content(node) {
 	e(node, 'textarea_invalid_content', `A \`<textarea>\` can have either a value attribute or (equivalently) child content, but not both\nhttps://svelte.dev/e/textarea_invalid_content`);
 }
 
-/**
- * `<title>` cannot have attributes nor directives
- * @param {null | number | NodeLike} node
- * @returns {never}
- */
-export function title_illegal_attribute(node) {
-	e(node, 'title_illegal_attribute', `\`<title>\` cannot have attributes nor directives\nhttps://svelte.dev/e/title_illegal_attribute`);
-}
-
 /**
  * `<title>` can only contain text and {tags}
  * @param {null | number | NodeLike} node
@@ -1647,4 +1638,4 @@ export function unterminated_string_constant(node) {
  */
 export function void_element_invalid_content(node) {
 	e(node, 'void_element_invalid_content', `Void elements cannot have children or closing tags\nhttps://svelte.dev/e/void_element_invalid_content`);
-}
+}

packages/svelte/src/compiler/phases/2-analyze/visitors/TitleElement.js

@@ -7,10 +7,6 @@ import * as e from '../../../errors.js';
  * @param {Context} context
  */
 export function TitleElement(node, context) {
-	for (const attribute of node.attributes) {
-		e.title_illegal_attribute(attribute);
-	}
-
 	for (const child of node.fragment.nodes) {
 		if (child.type !== 'Text' && child.type !== 'ExpressionTag') {
 			e.title_invalid_content(child);