AK+Everywhere: Turn bool keep_empty to an enum in split* functions

Author: https://github.com/demostanis
Commit: 3e8b5ac920
Pull-request: https://github.com/SerenityOS/serenity/pull/15750
Reviewed-by: https://github.com/AtkinsSJ
Reviewed-by: https://github.com/davidot
Reviewed-by: https://github.com/linusg ✅

Kernel/CommandLine.cpp

@@ -65,7 +65,7 @@ UNMAP_AFTER_INIT void CommandLine::add_arguments(Vector<StringView> const& args)
             continue;
         }
 
-        auto pair = str.split_view('=', false);
+        auto pair = str.split_view('=');
         VERIFY(pair.size() == 2 || pair.size() == 1);
 
         if (pair.size() == 1) {