> Rustdoc has a search bar at the top.
Let me assure you that I mean only the best for this language and I appreciate your persistent willingness to help, but I want to help debug your use of internal terminology that doesn't help beginners.
"rustdoc" is not how you should be telling beginners to look for documentation. As far as I can tell, "rustdoc" is the tool for generating documentation, not searching it. I assume you use rustdoc a lot and that's why the name comes to mind.
Maybe the term is overloaded, but I cannot find anything called "rustdoc" that involves a search bar. Googling for "rustdoc" gives many forms of Rust documentation, none of which have a search bar. DuckDuckGo-ing for "rustdoc" (as some documentation suggests instead of Googling) gets me some of the same things, plus rustdoc.com, which is a big honking security warning on top of someone's broken personal blog.
I know that exact link you gave me includes a search bar, but that's an example of finding the answer because you already know it.
And if you know to go to doc.rust-lang.org and go to the Standard Library API Reference, you get a search bar, but that's not where I would think of going to answer the question "how do I iterate lines".
That's why I end up Googling and getting to Stack Overflow, full of wrong answers and someone named Shepmaster yelling at newbies.