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/LibLine/SuggestionManager.h

@@ -27,7 +27,7 @@ public:
 
     // Intentionally not explicit. (To allow suggesting bare strings)
     CompletionSuggestion(String const& completion)
-        : CompletionSuggestion(completion, "", {})
+        : CompletionSuggestion(completion, ""sv, {})
     {
     }
 
@@ -36,7 +36,7 @@ public:
     {
     }
 
-    CompletionSuggestion(StringView completion, StringView trailing_trivia, StringView display_trivia = "")
+    CompletionSuggestion(StringView completion, StringView trailing_trivia, StringView display_trivia = ""sv)
         : CompletionSuggestion(completion, trailing_trivia, display_trivia, {})
     {
     }