chore(clippy): enable and fix many stricter lints (#3783)

* chore(clippy): enable and fix many stricter lints

These ensure that the codebase uses more idiomatic, performant, and
concise language constructions.

* chore: make non-Clippy compiler warnings also deny by default

apps/labrinth/tests/common/api_v2/project.rs

@@ -1,4 +1,4 @@
-use std::collections::HashMap;
+use std::{collections::HashMap, fmt::Write};
 
 use crate::{
     assert_status,
@@ -490,13 +490,13 @@ impl ApiProject for ApiV2 {
             featured = featured
         );
         if let Some(title) = title {
-            url.push_str(&format!("&title={title}"));
+            write!(&mut url, "&title={title}").unwrap();
         }
         if let Some(description) = description {
-            url.push_str(&format!("&description={description}"));
+            write!(&mut url, "&description={description}").unwrap();
         }
         if let Some(ordering) = ordering {
-            url.push_str(&format!("&ordering={ordering}"));
+            write!(&mut url, "&ordering={ordering}").unwrap();
         }
 
         let req = test::TestRequest::post()
@@ -521,11 +521,12 @@ impl ApiProject for ApiV2 {
         );
 
         for (key, value) in patch {
-            url.push_str(&format!(
+            write!(
+                &mut url,
                 "&{key}={value}",
-                key = key,
                 value = urlencoding::encode(&value)
-            ));
+            )
+            .unwrap();
         }
 
         let req = test::TestRequest::patch()