Correct a couple comments

src/note.rs

@@ -177,7 +177,7 @@ impl Note {
         self.value
     }
 
-    /// Derives the ephemeral secret key for this note.
+    /// Returns the rseed value of this note.
     pub(crate) fn rseed(&self) -> &RandomSeed {
         &self.rseed
     }

src/note/nullifier.rs

@@ -26,7 +26,7 @@ impl Nullifier {
     /// from the uniqueness of $\rho$.
     ///
     /// Instead of explicitly sampling for a unique nullifier, we rely here on the size of
-    /// the base field to make the chance of sapling a colliding nullifier negligible.
+    /// the base field to make the chance of sampling a colliding nullifier negligible.
     pub(crate) fn dummy(rng: &mut impl RngCore) -> Self {
         Nullifier(extract_p(&pallas::Point::random(rng)))
     }