Suppress or fix clippy pedantic lints

[vbrandl]

Running clippy with the pedantic lints (cargo clippy --tests -- -Dclippy::all -Dclippy::pedantic) on a project using ructe will produce many errors. Most of them are like this:

error: used binding `_ructe_out_` which is prefixed with an underscore. A leading underscore signals that a binding will not be used

Would you prefer fixing the lints produced by clippy or allow all pedantic lints for the generated code (#[allow(clippy::pedantic)])?

[kaj]

The _ructe_out_ this kind of "intentionally bad" to avoid accidentally having the same variable name used for somtehing in a template, but that is kind of a hack, maybe ructe_out_ without the preceding dash would be unlikely enough.

Or maybe i should #[allow()] the underscore for that specific variable? If so, only the specific lint should be allowed, not the whole "pedantic" group.

The other lints are probably just new lints I hadn't checked for yet (unless they come from the actual templates). I havn't really been that active in developing ructe the last year or so, but I should pick it up a bit, and PR:s are wellcome.