doc: learn about ipfs::error::TryError, document it
+///! IPFS crate wide errors.
+///!
+///! The error handling in `ipfs` is subject to change in the future.
+
+/// Just re-export anyhow for now.
+///
+/// # Stability
+///
+/// Very likely to change in the future.
pub use anyhow::Error;
+/// A try conversion failed.
+///
+/// # Stability
+///
+/// Very likely to change in the future.
pub struct TryError;
