AK: Convert AK::Format formatting helpers to returning ErrorOr<void>

This isn't a complete conversion to ErrorOr<void>, but a good chunk.
The end goal here is to propagate buffer allocation failures to the
caller, and allow the use of TRY() with formatting functions.

AK/Utf16View.h

@@ -123,9 +123,9 @@ private:
 
 template<>
 struct AK::Formatter<AK::Utf16View> : Formatter<FormatString> {
-    void format(FormatBuilder& builder, AK::Utf16View const& value)
+    ErrorOr<void> format(FormatBuilder& builder, AK::Utf16View const& value)
     {
-        return builder.builder().append(value);
+        return builder.builder().try_append(value);
     }
 };