Adding convenience append(range)

test/format-test.cc

@@ -236,7 +236,7 @@ TEST(MemoryBufferTest, MoveCtorInlineBuffer) {
   std::allocator<char> alloc;
   basic_memory_buffer<char, 5, TestAllocator> buffer((TestAllocator(&alloc)));
   const char test[] = "test";
-  buffer.append(test, test + 4);
+  buffer.append(string_view(test, 4));
   check_move_buffer("test", buffer);
   // Adding one more character fills the inline buffer, but doesn't cause
   // dynamic allocation.