Prevent the addition of space in type() with + (#19516)

Co-authored-by: fisker Cheung <lionkay@gmail.com>

changelog_unreleased/css/19516.md

@@ -0,0 +1,21 @@
+#### Prevent addition space in `type()` with `+` (#19516 by @bigandy)
+
+This fixes the addition space before `+` in CSS `type()` declaration. For example `type(<number>+)` was being converted into `type(<number> +)` which is invalid CSS and does not work.
+
+<!-- prettier-ignore -->
+```css
+/* Input */
+div {
+  border-radius: attr(br type(<length>+));
+}
+
+/* Prettier stable */
+div {
+  border-radius: attr(br type(<length> +));
+}
+
+/* Prettier main */
+div {
+  border-radius: attr(br type(<length>+));
+}
+```