chore: speed up regex (#11918)

This regex can take longer than expected in certain situations, making it more explicit and adding "not a whitespace" to the set speeds it up
Related https://github.com/sveltejs/language-tools/issues/2363

.changeset/itchy-peaches-compare.md

@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+chore: speed up regex

packages/svelte/src/compiler/preprocess/index.js

@@ -248,9 +248,9 @@ function stringify_tag_attributes(attributes) {
 }
 
 const regex_style_tags =
-	/<!--[^]*?-->|<style((?:\s+[^=>'"/]+=(?:"[^"]*"|'[^']*'|[^>\s]+)|\s+[^=>'"/]+)*\s*)(?:\/>|>([\S\s]*?)<\/style>)/g;
+	/<!--[^]*?-->|<style((?:\s+[^=>'"/\s]+=(?:"[^"]*"|'[^']*'|[^>\s]+)|\s+[^=>'"/\s]+)*\s*)(?:\/>|>([\S\s]*?)<\/style>)/g;
 const regex_script_tags =
-	/<!--[^]*?-->|<script((?:\s+[^=>'"/]+=(?:"[^"]*"|'[^']*'|[^>\s]+)|\s+[^=>'"/]+)*\s*)(?:\/>|>([\S\s]*?)<\/script>)/g;
+	/<!--[^]*?-->|<script((?:\s+[^=>'"/\s]+=(?:"[^"]*"|'[^']*'|[^>\s]+)|\s+[^=>'"/\s]+)*\s*)(?:\/>|>([\S\s]*?)<\/script>)/g;
 
 /**
  * Calculate the updates required to process all instances of the specified tag.