rust: patch bilge-impl to allow compilation with 1.63.0

Apply a patch that removes "let ... else" constructs, replacing them with
"if let ... else" or "let ... = match ...".  "let ... else" was stabilized in
Rust 1.65.0.

Reviewed-by: Junjie Mao <junjie.mao@hotmail.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

.gitattributes

@@ -5,3 +5,5 @@
 *.rs            diff=rust
 *.rs.inc        diff=rust
 Cargo.lock      diff=toml merge=binary
+
+*.patch         -text -whitespace