Can't render when comments contain non-ASCII characters

[HaleyHalcyon]

I tried to render a shader, but loading it raised a text encoding error. This error arose at several different parts of the code:

Traceback (most recent call last):
  File "D:\Downloads\shadertoy-render\shadertoy-render.py", line 926, in <module                                     >
    glsl_shader = open(args.input, 'r').read().encode('ascii', errors='ignore').                                     decode()
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
UnicodeDecodeError: 'cp932' codec can't decode byte 0x99 in position 2192: illeg                                     al multibyte sequence

This is a typical error caused by not specifying a character encoding to the open function, and can be fixed by adding , encoding='utf-8' to the function's parameters.

There should not be any incompatibility issues, since UTF-8 is backwards compatible to ASCII in the 0x00~0x7F range, the only range that GLSL cares about.