mk_graph: elide unnecessary lifetime in render_function

Remove the explicit lifetime parameter from `render_function` after rendered graph structures became fully owned and no longer borrow MIR data.

This addresses Clippy's `needless_lifetimes` warning and simplifies the traversal API.

Author: 0xh4ty

src/mk_graph/traverse.rs

@@ -134,11 +134,11 @@ pub fn render_graph<B: GraphBuilder>(smir: &SmirJson, mut builder: B) -> B::Outp
 
 /// Emit graph events for a single function body.
 /// Traverses blocks, CFG edges, and call edges without renderer-specific logic.
-fn render_function<'a>(
+fn render_function(
     ctx: &GraphContext,
     name: &str,
     symbol_name: &str,
-    body: Option<&'a Body>,
+    body: Option<&Body>,
 ) -> RenderedFunction {
     let id = match body {
         Some(b) => format!("fn_{}_{}", short_name(name), hash_body(b)),