This allows you to pass a template or a macro to another macro
which can then inspect the implementation of the former template/macro
using `getImpl`.
Since templates can be freely redefined, this allows you to treat
their symbols as compile-time variables that have lexical scope.
A motivating PoC example for a logging library taking advantage of
this will be provided in the next commit.
Implementation details:
* The name of a template or a macro will be consider a symbol if
the template/macro requires parameters
* For parameterless templates/macros, you can use `bindSym`, which
was extended to also work outside of compile-time procs.
