Fix many clippy warnings

This is because the tracing-attributes update made clippy look at those
again. I've removed the `too_many_lines` lint, as it's not really useful
and we ignore it most of the time anyway.

crates/syn2mas/src/synapse_reader/config/oidc.rs

@@ -193,7 +193,6 @@ impl OidcProvider {
     }
 
     /// Map this Synapse OIDC provider config to a MAS upstream provider config.
-    #[expect(clippy::too_many_lines)]
     pub(crate) fn into_mas_config(
         self,
         rng: &mut impl Rng,