main : fix bug (penalize_nl=false doesn't work) + suppress warning on mingw (#1528)

main : fix bug (penalize_nl=false doesn't work) + suppress warning on mingw (#1528)

* Fix bug in main.cpp where penalize_nl=false has no effect. It modifies the underlying logits array, but at this point we are already working on the candidates copy.

* Suppress redefinition warning for NOMINMAX on mingw. In my installation, this macro is already defined by /usr/lib/gcc/x86_64-w64-mingw32/11/include/c++/x86_64-w64-mingw32/bits/os_defines.h:45.

* main : fix indentation

* main : pass ctx to llama_token_nl()

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Co-authored-by: Georgi Gerganov <redacted>