Minor fixups in the generator

Also removes unused additional impl support

Author: DJMcNab

fearless_simd_core/gen/src/data/x86.rs

@@ -4,7 +4,6 @@ macro_rules! f {
     ($(#[doc = $doc_addition: literal])*
         struct $module: ident:: $struct_name: ident($display_name: literal): $feature_name: literal + [$($implicitly_enabled: literal),*]
         fn $example_function_name: ident
-        $($additional_impls: tt)*
     ) => {
         Feature {
             struct_name: stringify!($struct_name),
@@ -13,7 +12,6 @@ macro_rules! f {
             extra_docs: concat!($($doc_addition, "\n",)*),
             example_function_name: stringify!($example_function_name),
             feature_docs_name: $display_name,
-            additional_impls: stringify!($($additional_impls)*),
             module: stringify!($module)
         }
     }
@@ -285,7 +283,7 @@ pub(crate) const X86_FEATURES: &[Feature] = &[
         /// ["rdseed"] --- Read random seed
         ///
         /// ["rdseed"]: https://en.wikipedia.org/wiki/RdRand
-        struct crypto::Rdseed("`rdseed"): "rdseed" + []
+        struct crypto::Rdseed("`rdseed`"): "rdseed" + []
         fn uses_rdseed
     ),
     f!(

fearless_simd_core/gen/src/main.rs

@@ -104,9 +104,6 @@ struct Feature {
     example_function_name: &'static str,
     /// The "display name" for the feature, used inside the docs.
     feature_docs_name: &'static str,
-    /// Extra code added at the end.
-    /// Used for implicitly enabled features.
-    additional_impls: &'static str,
     /// The module (if any) this feature will belong to.
     ///
     /// (Note that imports into the module are checked to exist, but not automatically inserted).

fearless_simd_core/gen/templates/x86.rs

@@ -62,16 +62,16 @@ impl FEATURE_STRUCT_NAME {
     }
 
     #[target_feature(enable = "{FEATURE_ID}")]
-    /// Create a new token for the "{FEATURE_ID}" target feature is enabled.
+    /// Create a new token for the "{FEATURE_ID}" target feature.
     ///
     /// This method is useful to get a new token if you have an external proof that
-    /// {FEATURE_ID} is available. This could happen if you are in a target feature
+    /// {FEATURE_DOCS_NAME} is available. This could happen if you are in a target feature
     /// function called by an external library user.
     ///
     /// # Safety
     ///
     /// No conditions other than those inherited from the target feature attribute,
-    /// i.e. that the "{FEATURE_DOCS_NAME}" target feature is available.
+    /// i.e. that the "{FEATURE_ID}" target feature is available.
     ///
     /// [implicitly enables]: https://doc.rust-lang.org/beta/reference/attributes/codegen.html?highlight=implicitly%20enabled#r-attributes.codegen.target_feature.safety-restrictions
     pub fn new() -> Self {