Update README.md

[CorpusCallosum]

fix for code sample formatting sample - should be 4 tildes

[CorpusCallosum]

Oh yes you're right, the description states 3 tildes, but if you look at any of the documentation source files, they are using 4 tildes. For example: https://raw.githubusercontent.com/openframeworks/ofSite/master/documentation/math/ofMath_functions.markdown

hmmm Now I'm confused, should it actually be 3 tildes, or 4 tildes? 🤔

[dimitre]

from what I read now it can be three or more, tildes or backtick backtick and it works great in github with syntax coloring so I got used with it. I would change documentation to suggest using it. Ideas? @ofTheo

```c++
void main() {
    std::exit(0);
}
```

void main() {
    std::exit(0);
}

vs tilde

void main() {
    std::exit(0);
}

EDIT: I found tildes work well but it doesn't go with the file extension between brackets,