Add documentation to the modules

1. Missing documentation for the trace module in lambda-runtime/src/layers/mod.rs:
   • Added: /// Tracing utilities for Lambda runtime.

2. Missing documentation for the request_span function in lambda-runtime/src/layers/trace.rs:
   • Added documentation explaining what the function does and its behavior with different context parameters

Author: FullyTyped

lambda-runtime/src/layers/mod.rs

@@ -4,6 +4,7 @@ mod api_response;
 mod panic;
 
 // Publicly available services.
+/// Tracing utilities for Lambda runtime.
 pub mod trace;
 
 pub(crate) use api_client::RuntimeApiClientService;

lambda-runtime/src/layers/trace.rs

@@ -56,6 +56,10 @@ where
 
 /* ------------------------------------------- UTILS ------------------------------------------- */
 
+/// Creates a tracing span for a Lambda request with context information.
+///
+/// This function creates a span that includes the request ID and optionally
+/// the X-Ray trace ID and tenant ID if they are available in the context.
 pub fn request_span(ctx: &Context) -> tracing::Span {
     match (&ctx.xray_trace_id, &ctx.tenant_id) {
         (Some(trace_id), Some(tenant_id)) => {