rust: fix clippy lints

These were highlighted by the latest version of clippy (1.82.0).

rust/hg-core/src/ancestors.rs

@@ -206,11 +206,10 impl<G: Graph> MissingAncestors<G> {
             new_bases
                 .into_iter()
                 .filter(|&rev| rev != NULL_REVISION)
-                .map(|r| {
+                .inspect(|&r| {
                     if r > max_base {
                         max_base = r;
                     }
-                    r
                 }),
         );
         self.max_base = max_base;

rust/hg-core/src/revlog/filelog.rs

@@ -217,7 +217,7 pub struct FilelogRevisionData(Vec<u8>);
 impl FilelogRevisionData {
     /// Split into metadata and data
     pub fn split(&self) -> Result<(Option<&[u8]>, &[u8]), HgError> {
-        const DELIMITER: &[u8; 2] = &[b'\x01', b'\n'];
+        const DELIMITER: &[u8; 2] = b"\x01\n";
 
         if let Some(rest) = self.0.drop_prefix(DELIMITER) {
             if let Some((metadata, data)) = rest.split_2_by_slice(DELIMITER) {

rust/hg-core/src/revlog/inner_revlog.rs

@@ -802,9 +802,8 impl InnerRevlog {
             return Ok(func());
         }
         self.enter_writing_context(data_end, transaction)
-            .map_err(|e| {
+            .inspect_err(|_| {
                 self.exit_writing_context();
-                e
             })?;
         let res = func();
         self.exit_writing_context();