Incorrect reference to Stdlib.read_line

[cionx]

In section 7.1, we have the following sentence:

https://github.com/cs3110/textbook/blob/f20b28f70b19b06241a25c4431597d6af3b4e330/src/chapters/mut/refs.md?plain=1#L231-L233

This sentence claims that we have already seen the function Stdlib.read_line. But this function never appears (anywhere else) in the book. The only function named read_line that occurs in the book is Lwt_io.read_line, and even this function is only introduced in the next chapter (Chapter 8 on data structures).

[clarksmr]

Thank you! In assignments and labs before this topic (refs) in CS 3110, students have always seen Stdlib.read_line. But it's true that in the context of the textbook, the function is novel.