[Lazarus] LCL patch which fixes StringGrid Copy

[AlexeyT]

https://github.com/graemeg/lazarus/commit/961abc27b89c2f33b36d091225f0d351e3429073

   function PrepareToHTML(s: string): string;
   var
     i1: Integer;

     s1: string;

1) better i instead of i1,

2) make function param "s" - const param.

AT