Fix clippy.

src/wasm/additional_property.rs

@@ -1,4 +1,3 @@
-
 use std::collections::HashMap;
 
 use serde::Deserialize;
@@ -31,12 +30,6 @@ pub struct AdditionalProperties {
     pub(crate) properties: HashMap<String, AdditionalPropertyValue>,
 }
 
-impl AdditionalProperties {
-    pub(crate) fn get_elisp_names<'c>(&'c self) -> impl Iterator<Item = String> + 'c {
-        self.properties.keys().map(move |key| format!(":{}", key))
-    }
-}
-
 to_wasm!(
     AdditionalProperties,
     AffiliatedKeywords<'s>,