Add __ploc printf debugging helper

[0xEAB]

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[0xEAB]

Feel free to close, if something equivalent has already been added.

[crazymonkyyy]

__ploc(T)(T arg,int line=__line__,string file=__file__){
  import std.conv;
  arg.to!string.__ploc(line,file);
}
__ploc(string arg,int line=__line__,string file=__file__){
   ...
}