Meta: Port f1b79e0cd3 to gn build

Author: https://github.com/ADKaster
Commit: https://github.com/SerenityOS/serenity/commit/26a5d84d91
Pull-request: https://github.com/SerenityOS/serenity/pull/21697
Reviewed-by: https://github.com/alimpfard ✅

Meta/gn/secondary/AK/BUILD.gn

@@ -135,6 +135,7 @@ source_set("AK") {
     "SinglyLinkedList.h",
     "SinglyLinkedListSizePolicy.h",
     "SipHash.h",
+    "Slugify.h",
     "SourceGenerator.h",
     "SourceLocation.h",
     "Span.h",
@@ -211,6 +212,7 @@ source_set("sources") {
     "OptionParser.cpp",
     "Random.cpp",
     "SipHash.cpp",
+    "Slugify.cpp",
     "StackInfo.cpp",
     "Stream.cpp",
     "String.cpp",