bug(preprocessor): incorrect evaluation of local scopes

[gnikit]

Describe the bug
The preprocessor stack that would conditionally and locally be used to define a variable do not work.

To Reproduce

subroutine preprocessor_else(var)

#if 0
#define MYTYPE logical
#else
#define MYTYPE integer
#endif

MYTYPE :: var0  !< incorrect evaluation of MYTYPE

#undef MYTYPE

#if 1
#define MYTYPE real
#else
#define MYTYPE character
#endif

MYTYPE :: var1

endsubroutine preprocessor_else

Setup information (please complete the following information):

• OS: any
• Python Version [e.g. 3.10]
• fortls version: master
• Code editor used [e.g. VS Code, Vim]
• the Fortran extension for the code editor and its version [e.g. Modern Fortran v3.0.0] (if applicable)