Expose shared InDesign signature

crates/indd/src/lib.rs

@@ -3,11 +3,12 @@
 //! InDesign's binary document model is converted to IDML here. Applications can import the
 //! resulting package through [`craft_idml`] while retaining only their own model and UI mapping.
 
+pub use indd::header::SIGNATURE;
 pub use indd::{Conversion, Error, Preview, Warning};
 
 /// Whether `bytes` begins with the fixed signature of an InDesign document.
 pub fn is_indd(bytes: &[u8]) -> bool {
-    bytes.starts_with(&indd::header::SIGNATURE)
+    bytes.starts_with(&SIGNATURE)
 }
 
 /// Convert an InDesign document to IDML. `name` is the file name stored in the package.