update README example to match current implementation

- the .build() call is required to align with recent rework of
  serialization
- 'Type' was unused

The example is intended to match the one in
'engine/src/lib.rs' - which has also been updated to remove
the unused 'Type' and also 'rustfmt' the .build() call.

Author: mtovino-cloudflare

engine/README.md

@@ -12,22 +12,25 @@ an executable IR and, finally, executing filters against provided values.
 ## Example
 
 ```rust
-use wirefilter::{ExecutionContext, Scheme, Type};
+use wirefilter::{ExecutionContext, Scheme};
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     // Create a map of possible filter fields.
     let scheme = Scheme! {
         http.method: Bytes,
         http.ua: Bytes,
         port: Int,
-    };
+    }
+    .build();
 
     // Parse a Wireshark-like expression into an AST.
-    let ast = scheme.parse(r#"
-        http.method != "POST" &&
-        not http.ua matches "(googlebot|facebook)" &&
-        port in {80 443}
-    "#)?;
+    let ast = scheme.parse(
+        r#"
+            http.method != "POST" &&
+            not http.ua matches "(googlebot|facebook)" &&
+            port in {80 443}
+        "#,
+    )?;
 
     println!("Parsed filter representation: {:?}", ast);
 

engine/src/lib.rs

@@ -6,15 +6,16 @@
 //! # Example
 //!
 //! ```
-//! use wirefilter::{ExecutionContext, Scheme, Type};
+//! use wirefilter::{ExecutionContext, Scheme};
 //!
 //! fn main() -> Result<(), Box<dyn std::error::Error>> {
 //!     // Create a map of possible filter fields.
 //!     let scheme = Scheme! {
 //!         http.method: Bytes,
 //!         http.ua: Bytes,
 //!         port: Int,
-//!     }.build();
+//!     }
+//!     .build();
 //!
 //!     // Parse a Wireshark-like expression into an AST.
 //!     let ast = scheme.parse(