📝 Add PNA chunk naming convention docs

Expanded documentation for faCe and faCl chunk types to clarify their naming conventions according to PNA standards, explaining the semantic meaning of each character's case.

Author: ChanTsune

cli/src/chunk/acl.rs

@@ -8,11 +8,21 @@ use std::{
     str::{FromStr, Utf8Error, from_utf8},
 };
 
-/// [ChunkType] File Access Control Entry
+/// Private chunk type for File Access Control Entry.
+/// Name follows PNA chunk naming convention where case has semantic meaning:
+/// - lowercase first letter: ancillary (not critical)
+/// - lowercase second letter: private (not public)
+/// - uppercase third letter: reserved
+/// - lowercase fourth letter: safe to copy
 #[allow(non_upper_case_globals)]
 pub const faCe: ChunkType = unsafe { ChunkType::from_unchecked(*b"faCe") };
 
-/// [ChunkType] File Access Control List
+/// Private chunk type for File Access Control List.
+/// Name follows PNA chunk naming convention where case has semantic meaning:
+/// - lowercase first letter: ancillary (not critical)
+/// - lowercase second letter: private (not public)
+/// - uppercase third letter: reserved
+/// - lowercase fourth letter: safe to copy
 #[allow(non_upper_case_globals)]
 pub const faCl: ChunkType = unsafe { ChunkType::from_unchecked(*b"faCl") };