Everywhere: Add sv suffix to strings relying on StringView(char const*)

Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).

No functional changes.

Userland/Libraries/LibWeb/CSS/Selector.h

@@ -61,7 +61,7 @@ public:
                     result.append("n");
                 // - A is -1: Append "-n" to result.
                 else if (step_size == -1)
-                    result.append("-n");
+                    result.append("-n"sv);
                 // - A is non-zero: Serialize A and append it to result, then append "n" to result.
                 else if (step_size != 0)
                     result.appendff("{}n", step_size);