Minor contradiction after removing references to core_kernel

[prekel]

book/book/prologue/README.md

Lines 245 to 251 in 2eec2c8

	`Core` currently requires a UNIX based operating system, and so only
	works on systems like macOS, Linux, FreeBSD, and OpenBSD or the
	Windows Subsystem for Linux (WSL). `Core` is an extension of `Base`
	which works anywhere OCaml does, and in particular works on Windows
	and JavaScript. The examples in Part I of the book will for the most
	part use only `Base` and other highly portable
	libraries.[OCaml/operating system support]{.idx}

(introduced in #3454)

Core currently requires a UNIX based operating system
Core is an extension of Base which works anywhere OCaml does, and in particular works on Windows

Isn't this contradictory? I think is better to write something like " Core earlier requires a UNIX based operating system"

[yminsky]

The wording is confusing here.