Fix another typo in comments

packages/govuk-frontend/src/govuk/components/phase-banner/_index.scss

@@ -22,7 +22,7 @@
 
     // When forced colour mode is active, for example to provide high contrast,
     // the background colour of the tag is the same as the rest of the page. To ensure
-    // that the tag is perceived as separate the rest of the text in the phase banner,
+    // that the tag is perceived as separate to the rest of the text in the phase banner,
     // it is made bold.
     @media screen and (forced-colors: active) {
       font-weight: bold;