fixup: add indentation after template head

Co-authored-by: Jan Schultke <[email protected]>

Author: dietmarkuehl

source/exec.tex

@@ -6129,7 +6129,7 @@
     using operation_state_concept = operation_state_t;
 
     template<class R>
-    @\exposid{state}@(coroutine_handle<promise_type> h, R&& rr);
+      @\exposid{state}@(coroutine_handle<promise_type> h, R&& rr);
     ~@\exposid{state}@();
     void start() & noexcept;