Style: Consider allowing `and`, `or`, and `not` keywords in C++ code

C++ supports `and`, `or`, `not` [keywords](https://en.cppreference.com/w/cpp/keywords.html). `not` especially seems much more readable to me in `if`-clauses
```c++
if (not std::is_sorted(range)) {}
```
vs
```c++
if (!std::is_sorted(range)) {}
```
Currently we don't use them anywhere in the code base, mostly because the [Google C++ style guide]( https://google.github.io/styleguide/cppguide.html#Boolean_Expressions) disallows them
> Also note that you should always use the punctuation operators, such as && and ~, rather than the word operators, such as and and compl.

But IMO we should diverge for readability. Though this is coming from someone who was raised on Python.