Click through from procedure calls in src files

To explore a codebase I often click through the src, from a procedure call to the implementation of the procedure being called. For example
```f90
call some_procedure(x, y, z)
```
I would click (often ⌘+click) `some_procedure` in the above code and then be redirected to the implementation of `some_procedure` to learn more. i.e.
```f90
subroutine some_procedure(x, y, z)
implicit none
integer, intent(inout) :: x, y, z
! Some computation
end subroutine some_procedure
```
This sort of clicking through the src in the generated docs could be useful.