Auto merge of #20662 - mbrubeck:smallbitvec, r=nox

Update to smallbitvec 2.1

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- [x] `./mach build -d` does not report any errors
- [x] `./mach build-geckolib` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes do not require tests because covered by existing tests

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components/script/dom/cssstyledeclaration.rs

@@ -426,15 +426,14 @@ impl CSSStyleDeclarationMethods for CSSStyleDeclaration {
     // https://dev.w3.org/csswg/cssom/#the-cssstyledeclaration-interface
     fn IndexedGetter(&self, index: u32) -> Option<DOMString> {
         self.owner.with_block(|pdb| {
-            pdb.declarations().get(index as usize).map(|declaration| {
-                let important = pdb.declarations_importance().get(index);
-                let mut css = String::new();
-                declaration.to_css(&mut css).unwrap();
-                if important {
-                    css += " !important";
-                }
-                DOMString::from(css)
-            })
+            let declaration = pdb.declarations().get(index as usize)?;
+            let important = pdb.declarations_importance().get(index as usize)?;
+            let mut css = String::new();
+            declaration.to_css(&mut css).unwrap();
+            if important {
+                css += " !important";
+            }
+            Some(DOMString::from(css))
         })
     }