cursor: Clean up new "fallback"/"callback" docs

wayland-cursor/src/lib.rs

@@ -190,7 +190,9 @@ impl CursorTheme {
     ///
     /// This method returns [`None`] if this cursor is not provided either by the theme, or by one of its parents.
     ///
-    /// If a fallback is set, it will use the data from fallback
+    /// If a [fallback is set], it will use the data returned by the fallback.
+    ///
+    /// [fallback is set]: Self::set_callback()
     pub fn get_cursor(&mut self, name: &str) -> Option<&Cursor> {
         match self.cursors.iter().position(|cursor| cursor.name == name) {
             Some(i) => Some(&self.cursors[i]),
@@ -213,8 +215,8 @@ impl CursorTheme {
 
     /// Set a callback to load the cursor data, in case the system theme is missing a cursor that you need.
     ///
-    /// Your callback will be invoked with he name and size of the requested cursor and should return a byte
-    /// array with the contents of an `xcursor` file, or `None` if you don't provide a fallback for this cursor.
+    /// Your callback will be invoked with the name and size of the requested cursor and should return a byte
+    /// array with the contents of an `xcursor` file, or [`None`] if you don't provide a fallback for this cursor.
     ///
     /// For example, this defines a generic fallback cursor image and uses it for all missing cursors:
     /// ```ignore