Fix indentation for printing Fortran types with pointers

Fix indentation for printing Fortran types with pointers

Printing the prefix "PTR TO -> (" resp. "REF TO ->(" ignored the active
indentation level.  This caused inconsistent appearance of user-defined
Fortran types containing pointers.  Fix by using "fprintfi_filtered" with the
current indentation level for outputting the prefix string.  Add test case
ptr-indentation.

Example using 'ptype' on object of type:
  type TypeWithPointer
    integer i
    integer, pointer:: p
  end type TypeWithPointer

Before:
  type = Type typewithpointer
      integer(kind=4) :: i
  PTR TO -> ( integer(kind=4) :: p)
  End Type typewithpointer

After:
  type = Type typewithpointer
      integer(kind=4) :: i
      PTR TO -> ( integer(kind=4) :: p)
  End Type typewithpointer