Fallback to non variant matches when no matching variant exists

Svelte’s dynamic class syntax looks like this:
<h1 class:text-blue-500={shouldBeBlue}></h1>

We were picking up `class:text-blue-500` as a variant. However `class` is not a registered variant. In this case we were discarding the already matched rules for text-blue-500. In this case we want to match them anyway.

src/lib/generateRules.js

@@ -146,7 +146,7 @@ function applyVariant(variant, matches, context) {
     return result
   }
 
-  return []
+  return matches
 }
 
 function parseRules(rule, cache, options = {}) {

tests/variants.test.css

@@ -7,6 +7,10 @@
   --tw-ring-offset-shadow: 0 0 #0000;
   --tw-ring-shadow: 0 0 #0000;
 }
+.text-blue-500 {
+  --tw-text-opacity: 1;
+  color: rgba(59, 130, 246, var(--tw-text-opacity));
+}
 .shadow-md {
   --tw-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
   box-shadow: var(--tw-ring-offset-shadow, 0 0 #0000), var(--tw-ring-shadow, 0 0 #0000),

tests/variants.test.html

@@ -64,5 +64,8 @@
     <div class="lg:dark:shadow-md"></div>
     <div class="xl:dark:disabledshadow-md"></div>
     <div class="2xl:dark:motion-safe:focus-within:shadow-md"></div>
+
+    <!-- Things that look like variants but are not -->
+    <h1 class:text-blue-500={shouldBeBlue}></h1>
   </body>
 </html>