Fix -Wmissing-braces warnings

test/beast/core/buffers_generator.cpp

@@ -62,10 +62,10 @@ struct test_buffers_generator
         if (!buffer_bytes(cur_)) {
             if (iterations_) {
                 cur_ = const_buffers_type(
-                    underlying_buffer_sequence{
+                    underlying_buffer_sequence{{
                         net::buffer("abcde", iterations_),
                         net::buffer("12345", iterations_),
-                    });
+                    }});
                 iterations_ -= 1;
             }
             if(emulate_error_ && iterations_ == 3)

test/doc/websocket_2_handshaking.cpp

@@ -144,11 +144,11 @@ snippets()
             // an array of protocols supported by this server
             // in descending order of preference
             static const std::array<string_view, 3>
-                supported = {
+                supported = {{
                 "v3.my.chat",
                 "v2.my.chat",
                 "v1.my.chat"
-            };
+            }};
 
             std::string result;