doc: Add missing template text

There are two fake classes in qendian.h that exist only documenting
a lot of operator functions, but now that clang is being used to parse
all C++ code, when a class is a template class, clangqdoc must see its
template stuff to recognize template type T, for example. Hence, this
update adds template<typename T> to some fake class declarations used
only for documentation purposes. ie, inside #ifdef Q_CLANG_QDOC.

Change-Id: I1988b77cd7f3bb97067e7107dd00de34770e9fed
Reviewed-by: Topi Reiniö <topi.reinio@qt.io>

src/corelib/global/qendian.h

@@ -272,7 +272,8 @@ public:
     static Q_DECL_CONSTEXPR T fromSpecial(T source) { return qFromBigEndian(source); }
 };
 
-#ifdef Q_QDOC
+#ifdef Q_CLANG_QDOC
+template<typename T>
 class QLEInteger {
 public:
     explicit Q_DECL_CONSTEXPR QLEInteger(T i);
@@ -292,6 +293,7 @@ public:
     QLEInteger &operator ^=(T i);
 };
 
+template<typename T>
 class QBEInteger {
 public:
     explicit Q_DECL_CONSTEXPR QBEInteger(T i);