Remove doc::ItemType::class method

We only query the item class for two variants.  It is easier to hardcode
this two classes instead of providing all available classes.

src/doc.rs

@@ -243,37 +243,6 @@ impl ItemType {
         }
     }
 
-    pub fn class(&self) -> &str {
-        match self {
-            ItemType::Module => "module",
-            ItemType::ExternCrate => "extern-crate",
-            ItemType::Import => "import",
-            ItemType::Struct => "struct",
-            ItemType::Enum => "enum",
-            ItemType::Function => "function",
-            ItemType::Typedef => "type",
-            ItemType::Static => "static",
-            ItemType::Trait => "trait",
-            ItemType::Impl => "impl",
-            ItemType::TyMethod => "required-method",
-            ItemType::Method => "method",
-            ItemType::StructField => "structfield",
-            ItemType::Variant => "variant",
-            ItemType::Macro => "macro",
-            ItemType::Primitive => "primitive",
-            ItemType::AssocType => "associated-type",
-            ItemType::Constant => "constant",
-            ItemType::AssocConst => "associated-const",
-            ItemType::Union => "union",
-            ItemType::ForeignType => "foreign-type",
-            ItemType::Keyword => "keyword",
-            ItemType::OpaqueTy => "opaque-type",
-            ItemType::ProcAttribute => "proc-attribute",
-            ItemType::ProcDerive => "proc-derive",
-            ItemType::TraitAlias => "trait-alias",
-        }
-    }
-
     pub fn group_name(&self) -> &str {
         match self {
             ItemType::Module => "Modules",

src/parser/mod.rs

@@ -275,7 +275,7 @@ fn get_fields(
     let mut definition: Option<doc::Text> = None;
 
     while let Some(element) = &next {
-        if element.is_element(&local_name!("span")) && element.has_class(ty.class()) {
+        if element.is_element(&local_name!("span")) && element.has_class("structfield") {
             fields.push(&mut name, &mut definition, None)?;
             name = get_id_part(element, 1);
             definition = Some(element.into());
@@ -476,7 +476,7 @@ fn get_variants(
     let mut definition: Option<doc::Text> = None;
     while let Some(element) = &next {
         if element.is_element(&local_name!("div")) {
-            if element.has_class(ty.class()) {
+            if element.has_class("variant") {
                 variants.push(&mut name, &mut definition, None)?;
                 name = get_id_part(element, 1);
                 definition = Some(element.into());