Rollup merge of #80794 - LingMan:map_or, r=jyn514

Use Option::map_or instead of `.map(..).unwrap_or(..)`

r? `@jyn514`
`@rustbot` modify labels +C-cleanup +T-rustdoc

Author: JohnTitor

src/librustdoc/clean/mod.rs

@@ -942,7 +942,7 @@ impl<'a> Clean<Arguments> for (&'a [hir::Ty<'a>], &'a [Ident]) {
                 .iter()
                 .enumerate()
                 .map(|(i, ty)| {
-                    let mut name = self.1.get(i).map(|ident| ident.name).unwrap_or(kw::Empty);
+                    let mut name = self.1.get(i).map_or(kw::Empty, |ident| ident.name);
                     if name.is_empty() {
                         name = kw::Underscore;
                     }
@@ -1001,7 +1001,7 @@ impl<'tcx> Clean<FnDecl> for (DefId, ty::PolyFnSig<'tcx>) {
                     .iter()
                     .map(|t| Argument {
                         type_: t.clean(cx),
-                        name: names.next().map(|i| i.name).unwrap_or(kw::Empty),
+                        name: names.next().map_or(kw::Empty, |i| i.name),
                     })
                     .collect(),
             },