doc(c-api) Specify that the code does not panic.

lib/c-api/src/wasm_c_api/instance.rs

@@ -18,13 +18,16 @@ pub struct wasm_instance_t {
 ///
 /// ## Errors
 ///
-/// The function can fail in 2 ways, as defined by the specification:
+/// The function can fail in 2 ways:
 ///
 /// 1. Link errors that happen when plugging the imports into the
 ///    instance,
 /// 2. Runtime errors that happen when running the module `start`
 ///    function.
 ///
+/// Failures are stored in the `traps` argument; the program doesn't
+/// panic.
+///
 /// # Notes
 ///
 /// The `store` argument is ignored. The store from the given module