C++ highlighting ignores class keyword if it is not followed by a space
template<class T> struct X; // ok
template<class> struct X; // fails
template<class...> struct X; // fails
X<class::Y> x; // fails
This was done to speed up incremental compilation when working on
lexers. That is, modifying a single lexer will no longer require
recompiling all lexers.
This is a (slightly) backwards breaking change in that lexers are no
longer exported directly in the lexers package. The registry API is
"aliased" at the old location.
