traits.md said:

If we add a `use` line right above `main` and make the right things public,
everything is fine:

However, the use line was actually placed at the top of the file instead.  Move
the use line to right above main.  That also makes the example more evocative
of cases where the module is defined in a separate file.

There is no `read_string` function, and `lines` never returns an error.

 cc @steveklabnik

 Fixes rust-lang#24030

Of the four code samples with modules in TRPL:

    - 2 use `mod test`
    - 2 use `mod tests`

We should be consistent here, but which is right? The stdlib is split:

    $ grep -r 'mod tests {' src/lib* | wc -l
          63
    $ grep -r 'mod test {'  src/lib* | wc -l
          58

Subjectively, I like the plural, but both the language reference and the
style guide recommend the singular. So we'll go with that here, for now.

r? @steveklabnik

…d-error, r=huon

…a-docs, r=huon

 This probably needs a bit more work, but I wanted to try and capture some common use cases and be a bit more helpful.

r? @huonw
cc @steveklabnik

 Fixes rust-lang#24060.

 traits.md said:

If we add a `use` line right above `main` and make the right things public,
everything is fine:

However, the use line was actually placed at the top of the file instead.  Move
the use line to right above main.  That also makes the example more evocative
of cases where the module is defined in a separate file.

 * Fix broken \"module-level documentation\" link on the [`trait Any` docs](http://doc.rust-lang.org/std/any/trait.Any.html) and related broken markup on the [`std::any` docs](http://doc.rust-lang.org/std/any/index.html).

* Remove an outdated or incorrect notice in the `BufRead::lines` docs. There is no such `read_string` function, and `lines` never returns an error.

r? @steveklabnik