docs(xtream): restore the docblock currentSourceRow lost to an insertion

routeCategoryLanguage was added between currentSourceRow's docblock and
its signature, so the paragraph describing "the row standing for the
source the route is already playing" ended up introducing a function
that returns a language string. Moved below; no behavior change.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

libs/portal/xtream/feature/src/lib/vod-details/vod-multi-source-current-row.ts

@@ -21,21 +21,6 @@ import type { VodMultiSourceMovie } from './vod-multi-source-identity';
  * not fire on a route-to-alternative switch, which is the commonest one there
  * is.
  */
-/**
- * The route row's category-derived language: what the one category the route
- * arrived through states, if that is a language. Alternatives read this off
- * every category the DB knows; the route only knows the visible one. Shared
- * with the host's refresh path so the two cannot drift — the category loads
- * late on cold/direct routes and arrives without changing the movie key.
- */
-export function routeCategoryLanguage(
-    movie: VodMultiSourceMovie
-): string | null {
-    return unambiguousCategoryLanguage(
-        movie.categoryName ? [movie.categoryName] : null
-    );
-}
-
 export function currentSourceRow(
     movie: VodMultiSourceMovie
 ): VodSourceCandidate {
@@ -53,3 +38,18 @@ export function currentSourceRow(
 
     return movie.metadata ? applyApiMetadata(row, movie.metadata) : row;
 }
+
+/**
+ * The route row's category-derived language: what the one category the route
+ * arrived through states, if that is a language. Alternatives read this off
+ * every category the DB knows; the route only knows the visible one. Shared
+ * with the host's refresh path so the two cannot drift — the category loads
+ * late on cold/direct routes and arrives without changing the movie key.
+ */
+export function routeCategoryLanguage(
+    movie: VodMultiSourceMovie
+): string | null {
+    return unambiguousCategoryLanguage(
+        movie.categoryName ? [movie.categoryName] : null
+    );
+}