MSVC warnings in binary_to_compressed_c.cpp

[Blinue]

Version/Branch of Dear ImGui:

Version: 1.87
Branch: master

Back-end/Renderer/Compiler/OS

Compiler: MSVC
Operating System: Windows

My Issue/Question:

Got warnings when compiling as x64 (build via Conan)

Warning: ...\misc\fonts\binary_to_compressed_c.cpp(263,28): warning C4244: '=': conversion from '__int64' to 'stb_uint', possible loss of data
Warning: ...\misc\fonts\binary_to_compressed_c.cpp(280,31): warning C4244: 'argument': conversion from '__int64' to 'int', possible loss of data 
Warning: ...\misc\fonts\binary_to_compressed_c.cpp(280,31): warning C4244: '=': conversion from '__int64' to 'int', possible loss of data 
Warning: ...\misc\fonts\binary_to_compressed_c.cpp(282,63): warning C4244: 'argument': conversion from '__int64' to 'int', possible loss of data 
...

[ocornut]

Pushed fixes, thank you!