fix doc compilation errors

Author: animafps

rustsynth/src/filter/mod.rs

@@ -98,7 +98,7 @@ impl FilterMode {
 
 /// A filter’s “getframe” function. It is called by the core when it needs the filter to generate a frame.
 /// It is possible to allocate local data, persistent during the multiple calls requesting the output frame.
-/// In case of error, call [setFilterError] and return [None].
+/// In case of error, call setFilterError and return [None].
 /// Depending on the [FilterMode] set for the filter, multiple output frames could be requested concurrently.
 /// It is never called concurrently for the same frame number.
 /// 

rustsynth/src/vsscript/mod.rs

@@ -65,6 +65,7 @@ impl ScriptAPI {
         }
     }
 
+    #[allow(unused)]
     pub(crate) fn get_api_version(&self) -> i32 {
         unsafe { self.handle.as_ref().getAPIVersion.unwrap()() }
     }