Merge pull request #882 from ehuss/1.54-path-attribute

Remove `#[path]` example from 1.54 blog post.

Author: Mark-Simulacrum

posts/2021-07-29-Rust-1.54.0.md

@@ -33,11 +33,29 @@ Rust 1.54 supports invoking function-like macros inside attributes. Function-lik
 #![doc = include_str!("README.md")]
 ```
 
-Macros can be nested inside the attribute as well, for example to include content generated by a build script:
+Macros can be nested inside the attribute as well.
+For example, the `concat!` macro can be used to construct a doc comment from within a macro that uses `stringify!` to include substitutions:
 
 ```rust
-#[path = concat!(env!("OUT_DIR"), "/generated.rs")]
-mod generated;
+macro_rules! make_function {
+    ($name:ident, $value:expr) => {
+        #[doc = concat!("The `", stringify!($name), "` example.")]
+        ///
+        /// # Example
+        ///
+        /// ```
+        #[doc = concat!(
+            "assert_eq!(", module_path!(), "::", stringify!($name), "(), ",
+            stringify!($value), ");")
+        ]
+        /// ```
+        pub fn $name() -> i32 {
+            $value
+        }
+    };
+}
+
+make_function! {func_name, 123}
 ```
 
 Read [here](https://github.com/rust-lang/rust/pull/83366) for more details.