Fix a couple docstrings (#641)

insta/src/snapshot.rs

@@ -424,7 +424,6 @@ impl Snapshot {
         ))
     }
 
-    /// Creates an empty snapshot.
     pub(crate) fn from_components(
         module_name: String,
         snapshot_name: Option<String>,
@@ -604,8 +603,10 @@ impl Snapshot {
     /// Same as [`Self::save`] but instead of writing a normal snapshot file this will write
     /// a `.snap.new` file with additional information.
     ///
-    /// The name of the new snapshot file is returned.
+    /// The path of the new snapshot file is returned.
     pub(crate) fn save_new(&self, path: &Path) -> Result<PathBuf, Box<dyn Error>> {
+        // TODO: should we be the actual extension here rather than defaulting
+        // to the standard `.snap`?
         let new_path = path.to_path_buf().with_extension("snap.new");
         self.save_with_metadata(&new_path, &self.metadata)?;
         Ok(new_path)