Merge pull request #1318 from gwenn/clippy_

Fix clippy warnings

src/busy.rs

@@ -1,4 +1,4 @@
-///! Busy handler (when the database is locked)
+//! Busy handler (when the database is locked)
 use std::convert::TryInto;
 use std::mem;
 use std::os::raw::{c_int, c_void};

src/lib.rs

@@ -1162,13 +1162,21 @@ mod test {
     // this function is never called, but is still type checked; in
     // particular, calls with specific instantiations will require
     // that those types are `Send`.
-    #[allow(dead_code, unconditional_recursion)]
+    #[allow(
+        dead_code,
+        unconditional_recursion,
+        clippy::extra_unused_type_parameters
+    )]
     fn ensure_send<T: Send>() {
         ensure_send::<Connection>();
         ensure_send::<InterruptHandle>();
     }
 
-    #[allow(dead_code, unconditional_recursion)]
+    #[allow(
+        dead_code,
+        unconditional_recursion,
+        clippy::extra_unused_type_parameters
+    )]
     fn ensure_sync<T: Sync>() {
         ensure_sync::<InterruptHandle>();
     }