docs: fix non-compiling README example and From/TryFrom mix-up

MsDosDateTime::new returns Option<Self> since 9cd9520, but the README
quick start was not updated and no longer compiled; it was also missing
the error type annotation on the content stream that type inference
needs. Align it with the compile-tested lib.rs doctest.

The jiff feature provides TryFrom<jiff::civil::DateTime>, not From, in
both the README feature table and the crate-level docs.

Author: paolobarbolini

README.md

@@ -20,13 +20,13 @@ use tokio::{fs::File, io::AsyncWriteExt};
 
 #[tokio::main(flavor = "current_thread")]
 async fn main() -> io::Result<()> {
-    let modified = MsDosDateTime::new(2026, 3, 10, 12, 30, 0);
+    let modified = MsDosDateTime::new(2026, 3, 10, 12, 30, 0).unwrap();
 
     let entries = stream::iter([
         Ok(ZipEntry::File {
             path: "hello.txt".into(),
             modified,
-            content: stream::iter([Ok(Bytes::from_static(b"Hello, world!"))]),
+            content: stream::iter([Ok::<_, io::Error>(Bytes::from_static(b"Hello, world!"))]),
         }),
         Ok(ZipEntry::Directory {
             path: "subdir/".into(),
@@ -60,7 +60,7 @@ async fn main() -> io::Result<()> {
 | Feature | Default | Description |
 |---------|---------|-------------|
 | `std`   | Yes     | Enables runtime SIMD detection for faster CRC-32. Everything works without it. |
-| `jiff`  | No      | Adds `From<jiff::civil::DateTime>` for `MsDosDateTime`. |
+| `jiff`  | No      | Adds `TryFrom<jiff::civil::DateTime>` for `MsDosDateTime`. |
 
 ## License
 

src/lib.rs

@@ -60,7 +60,7 @@
 //! # Features
 //!
 //! - **`std`** *(default)* - enables runtime SIMD detection for faster CRC-32.
-//! - **`jiff`** - adds `From<jiff::civil::DateTime>` for [`MsDosDateTime`].
+//! - **`jiff`** - adds `TryFrom<jiff::civil::DateTime>` for [`MsDosDateTime`].
 
 #![cfg_attr(not(feature = "std"), no_std)]