print_debug example uses the <> structure syntax before it has been introduced

The print_debug example does, in fact, have a link at the bottom to the structure example page. But so far, the "<>" part of the structure syntax has not yet been introduced, and the print_debug page does not explain its meaning.

Interestingly, the linked page does not use or refer to this syntax, either.

The syntax may feel familiar to C++ and other developers who have encountered templates. But being new to this, I am not sure if this syntax exactly mimics the semantics in those other languages, and I am not sure we can assume all rust learners have even used another programming language with similar syntax.

The struct example page should almost certainly introduce the <> syntax and provide instances of its use.

Read the print_debug example and its linked structure example page first. Introduce the <> structure syntax before it appears in print_debug, explain its meaning, and add examples of its use on the structure page; done means the documentation no longer uses unexplained syntax and the linked page addresses it.