Formatter: Remove extraneous char definition

Formatter is specialized in the header file. The definition in the
implementation file is extraneous and has no effect. Simply removing
it so that there is no confusion.

AK/Format.cpp

@@ -640,7 +640,6 @@ template struct Formatter<unsigned short, void>;
 template struct Formatter<unsigned int, void>;
 template struct Formatter<unsigned long, void>;
 template struct Formatter<unsigned long long, void>;
-template struct Formatter<char, void>;
 template struct Formatter<short, void>;
 template struct Formatter<int, void>;
 template struct Formatter<long, void>;