doc: fix intra-doc links (#30)

src/osu/mod.rs

@@ -100,9 +100,12 @@ impl<'map> OsuStars<'map> {
 
     /// Amount of passed objects for partial plays, e.g. a fail.
     ///
-    /// If you want to calculate the difficulty after every few objects, instead of
-    /// using [`OsuStars`] multiple times with different `passed_objects`, you should use
-    /// [`OsuGradualDifficulty`].
+    #[cfg_attr(
+        feature = "gradual",
+        doc = "If you want to calculate the difficulty after every few objects, instead of
+        using [`OsuStars`] multiple times with different `passed_objects`, you should use
+        [`OsuGradualDifficulty`]."
+    )]
     #[inline]
     pub fn passed_objects(mut self, passed_objects: usize) -> Self {
         self.passed_objects = Some(passed_objects);

src/osu/pp.rs

@@ -162,9 +162,12 @@ impl<'map> OsuPP<'map> {
 
     /// Amount of passed objects for partial plays, e.g. a fail.
     ///
-    /// If you want to calculate the performance after every few objects, instead of
-    /// using [`OsuPP`] multiple times with different `passed_objects`, you should use
-    /// [`OsuGradualPerformanceAttributes`](crate::osu::OsuGradualPerformance).
+    #[cfg_attr(
+        feature = "gradual",
+        doc = "If you want to calculate the performance after every few objects, instead of
+        using [`OsuPP`] multiple times with different `passed_objects`, you should use
+        [`OsuGradualPerformanceAttributes`](crate::osu::OsuGradualPerformance)."
+    )]
     #[inline]
     pub fn passed_objects(mut self, passed_objects: usize) -> Self {
         self.passed_objects = Some(passed_objects);