Update various parts of the text.

There's no such thing as "early ReferenceError" anymore (for things like 0++); they're all just "early SyntaxError" now. tc39/ecma262#691

• Dynamic variable naming.
• Internal variables.
• Turn the non-functions into functions.
  • This is so tests can be written.
  • It also shows a working use case for the task.
• Add a CONTRIBUTING.md.
• Look into side effects of using shopt and set.
• /dev/tcp
• Convert to pdf
  • Add a cover.
  • Add references.
• Write some

It says that python gets left to point to the system python (2.7 on OSX), but then goes on to say that python points to homebrew Python3.

https://github.com/realpython/python-guide/blame/master/docs/starting/install/osx.rst#L84-L89

Not sure which bit needs to be changed.

explanation behind that says it's just coercion of one type plus another.
What is happening there is actually a code block and a unary + which coerces the array into 0.
({} + []) would get the same as ([] + {}) understandably.

The input system usually includes a mouse and a key-board, while the output system usually consists of a monitor that can display a large mount amount of pixels.

This is a proposal to introduce, in the lifetime chapter 10.3, an explanation of why lifetime annotations are necessary at all. I think the concept of lifetime annotations can be understood easily, but I think that - being so peculiar to rust - it needs more grounded explanations to be fully assimilated in the reader.

The Book expla