fix(partial): Clarify Needed::Size is for offset, not tokens

Inspired by #578

src/binary/bits/tests.rs

@@ -59,7 +59,7 @@ fn test_incomplete_bits() {
 
     assert!(result.is_err());
     let error = result.err().unwrap();
-    assert_eq!("Parsing requires 2 bytes/chars", error.to_string());
+    assert_eq!("Parsing requires 2 more data", error.to_string());
 }
 
 #[test]

src/error.rs

@@ -63,7 +63,9 @@ pub type PResult<O, E = ContextError> = Result<O, ErrMode<E>>;
 pub enum Needed {
     /// Needs more data, but we do not know how much
     Unknown,
-    /// Contains the required data size in bytes
+    /// Contains a lower bound on the buffer offset needed to finish parsing
+    ///
+    /// For byte/`&str` streams, this translates to bytes
     Size(NonZeroUsize),
 }
 
@@ -253,7 +255,7 @@ where
 {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
-            ErrMode::Incomplete(Needed::Size(u)) => write!(f, "Parsing requires {u} bytes/chars"),
+            ErrMode::Incomplete(Needed::Size(u)) => write!(f, "Parsing requires {u} more data"),
             ErrMode::Incomplete(Needed::Unknown) => write!(f, "Parsing requires more data"),
             ErrMode::Cut(c) => write!(f, "Parsing Failure: {c:?}"),
             ErrMode::Backtrack(c) => write!(f, "Parsing Error: {c:?}"),