fix/improve rust getting started build.rs example + add docstring to Record::serialize

Runtime/Rust/src/serialization/mod.rs

@@ -43,6 +43,22 @@ pub trait Record<'raw>: SubRecord<'raw> {
     }
 
     /// Serialize this record. It is highly recommend to use a buffered writer.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// // For fixed-size types
+    /// let value: MyFixedSizeType = /* ... */;
+    /// let mut buf = Vec::with_capacity(MyFixedSizeType::SERIALIZED_SIZE);
+    /// let bytes_written = value.serialize(&mut buf).unwrap();
+    /// ```
+    /// ```rust
+    /// // For variable-size types
+    /// let value: MyVariableSizeType = /* ... */;
+    /// let size = value.serialized_size();
+    /// let mut buf = Vec::with_capacity(size);
+    /// let bytes_written = value.serialize(&mut buf).unwrap();
+    /// ```
     #[inline(always)]
     fn serialize<W: Write>(&self, dest: &mut W) -> SeResult<usize> {
         Self::_serialize_chained(self, dest)

docs/src/content/docs/guide/getting-started-rust.mdx

@@ -22,10 +22,10 @@ fn main() {
     // download the bebop binary automatically and cache it into your target directory
     // it will automatically download the same version as the package you installed
     bebop::download_bebopc(
-        PathBuf::from("target").join("bebopc"),
+        std::path::PathBuf::from("target").join("bebopc"),
     );
     // build all `.bop` schemas in `schemas` dir and make a new module `generated` in `src` with all of them.
-    bebop::build_schema_dir("schemas", "src/generated");
+    bebop::build_schema_dir("schemas", "src/generated", &bebop::BuildConfig::default());
 }
 ```