Fix or suppress pedantic clippy warnings

[vbrandl]

Two lints will fail if clippy::pedantic is enabled:

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

After the discussion in #126, I opted for #[allow(clippy::used_underscore_binding)] where _ructe_out_ is defined, as to not break any existing code

error: this method could have a `#[must_use]` attribute
  --> <snip>/out/templates/statics.rs:18:5
   |
18 |     pub fn get(name: &str) -> Option<&'static Self> {
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: add the attribute: `#[must_use] pub fn get(name: &str) -> Option<&'static Self>`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#must_use_candidate
   = note: `-D clippy::must-use-candidate` implied by `-D clippy::pedantic`

this is fixed by adding the `#[must_use]` attribute to the generated code

Fixes #126

[vbrandl]

Did you have time to review this? What are your thoughts?

[kaj]

Thanks! Yes, this looks good, though one change is is conflict (actually kinds of duplicates) a change that was part of another PR i just merged. I'll resolve that ...

[kaj]

Looks good to me!