[fix]: strip leading newline characters after 'pre' elements

Close #7264

package-lock.json

@@ -5,6 +5,7 @@
   "requires": true,
   "packages": {
     "": {
+      "name": "svelte",
       "version": "3.46.4",
       "license": "MIT",
       "devDependencies": {

src/compiler/parse/state/tag.ts

@@ -197,6 +197,14 @@ export default function tag(parser: Parser) {
 
 	parser.eat('>', true);
 
+	// A leading newline character immediately following the pre element start tag is stripped
+	// See spec: https://www.w3.org/TR/2011/WD-html5-20110113/grouping-content.html#the-pre-element
+	if (!is_closing_tag && name === 'pre') {
+		if (!parser.eat('\r\n')) {
+			parser.eat('\n');
+		}
+	}
+
 	if (self_closing) {
 		// don't push self-closing elements onto the stack
 		element.end = parser.index;

test/parser/samples/leading-newline-after-pre-tag/input.svelte

@@ -0,0 +1,3 @@
+<pre>
+test
+</pre>

test/parser/samples/leading-newline-after-pre-tag/output.json

@@ -0,0 +1,25 @@
+{
+	"html": {
+		"start": 0,
+		"end": 17,
+		"type": "Fragment",
+		"children": [
+			{
+				"start": 0,
+				"end": 17,
+				"type": "Element",
+				"name": "pre",
+				"attributes": [],
+				"children": [
+					{
+						"start": 6,
+						"end": 11,
+						"type": "Text",
+						"raw": "test\n",
+						"data": "test\n"
+					}
+				]
+			}
+		]
+	}
+}