Add build target for the provisional style guide.

This includes the provisional style guide in the website and fixes the broken
link from CONTRIBUTING.md. The style guide will be located under the "Community"
category as it's related to contributing to the project.

Also, add missing includes that were causing some presubmits to fail.

PiperOrigin-RevId: 319061410

g3doc/BUILD

@@ -33,3 +33,12 @@ doc(
     subcategory = "Community",
     weight = "95",
 )
+
+doc(
+    name = "style",
+    src = "style.md",
+    category = "Project",
+    permalink = "/community/style_guide/",
+    subcategory = "Community",
+    weight = "10",
+)

test/syscalls/linux/fcntl.cc

@@ -18,7 +18,10 @@
 #include <syscall.h>
 #include <unistd.h>
 
+#include <iostream>
+#include <list>
 #include <string>
+#include <vector>
 
 #include "gtest/gtest.h"
 #include "absl/base/macros.h"

website/BUILD

@@ -138,6 +138,7 @@ docs(
         "//g3doc:community",
         "//g3doc:index",
         "//g3doc:roadmap",
+        "//g3doc:style",
         "//g3doc/architecture_guide:performance",
         "//g3doc/architecture_guide:platforms",
         "//g3doc/architecture_guide:resources",