Typo in `std::convert` module docs

[AlexanderSerbul]

Location (URL)

https://doc.rust-lang.org/std/convert/index.html

Summary

"The traits in this module are often used as trait bounds for generic functions such that to arguments of multiple types are supported. "

"to" is excessive, I think. Thank you.

[Muhtasim-Rasheed]

@rustbot claim