gff/reader/records: Fix clippy::redundant_guards warning

This was added in Rust 1.73.0 / clippy 0.1.73 (cc66ad4 2023-10-03).

noodles-gff/src/reader/records.rs

@@ -33,7 +33,7 @@ where
         loop {
             match self.lines.next()? {
                 Ok(line) => match line {
-                    Line::Directive(d) if d == Directive::StartOfFasta => return None,
+                    Line::Directive(Directive::StartOfFasta) => return None,
                     Line::Record(r) => return Some(Ok(r)),
                     _ => {}
                 },