Change the canonical way to include the C bindings headers to <mojo/bindings/*.h>.

mojo/public/c/lib/bindings/buffer.c

Index: mojo/public/c/lib/bindings/buffer.c
diff --git a/mojo/public/c/bindings/lib/buffer.c b/mojo/public/c/lib/bindings/buffer.c
similarity index 85%
rename from mojo/public/c/bindings/lib/buffer.c
rename to mojo/public/c/lib/bindings/buffer.c
index e8d559671d83e2c3b41ab773ba235c44552a1178..8a76bec9a0b99bd1a789376e329f25c2f6ee8acc 100644
--- a/mojo/public/c/bindings/lib/buffer.c
+++ b/mojo/public/c/lib/bindings/buffer.c
@@ -2,13 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "mojo/public/c/bindings/buffer.h"
+#include <mojo/bindings/buffer.h>
 
 #include <assert.h>
+#include <mojo/bindings/internal/util.h>
 #include <stddef.h>
 
-#include "mojo/public/c/bindings/lib/util.h"
-
 void* MojomBuffer_Allocate(struct MojomBuffer* buf, uint32_t num_bytes) {
   assert(buf);