Align clang-format include ordering with cpplint rules (#1428)

Previously, clang-format's default Google style IncludeCategories assigned the same priority to C++ standard library headers (e.g., <string>) and third-party headers (e.g., <rcpputils/scope_exit.hpp>), causing them to be sorted alphabetically within the same group. This violated cpplint's expected include order (C system → C++ system → other), requiring `// NOLINTNEXTLINE` comments as workarounds.

Changes:
- .clang-format: Add explicit IncludeCategories to separate C++ standard library headers (no slash, no extension) from third-party angle-bracket headers, and set IncludeBlocks to Regroup so clang-format enforces proper grouping
- .clang-format: Upgrade Standard from Cpp11 to c++17 to match binding.gyp
- Remove `// NOLINTNEXTLINE` from 4 source files: src/rcl_context_bindings.cpp, src/rcl_graph_bindings.cpp, src/rcl_subscription_bindings.cpp, src/rcl_utilities.cpp

Verified with `npm run format` and `npm run lint` (cpplint: 0 errors).

Fix: #1427

Author: minggangw

.clang-format

@@ -1,2 +1,14 @@
 BasedOnStyle: Google
-Standard: Cpp11
+Standard: c++17
+IncludeBlocks: Regroup
+IncludeCategories:
+  - Regex:    '^<ext/.*\.h>'
+    Priority: 2
+  - Regex:    '^<.*\.h>'
+    Priority: 1
+  - Regex:    '^<[^./]+>'
+    Priority: 2
+  - Regex:    '^<.*'
+    Priority: 3
+  - Regex:    '.*'
+    Priority: 4

src/rcl_context_bindings.cpp

@@ -17,10 +17,10 @@
 #include <rcl/logging.h>
 #include <rcl/rcl.h>
 
-#include <rcpputils/scope_exit.hpp>
-// NOLINTNEXTLINE
 #include <string>
 
+#include <rcpputils/scope_exit.hpp>
+
 #include "macros.h"
 #include "rcl_handle.h"
 #include "rcl_utilities.h"

src/rcl_graph_bindings.cpp

@@ -18,10 +18,10 @@
 #include <rcl/graph.h>
 #include <rcl/rcl.h>
 
-#include <rcpputils/scope_exit.hpp>
-// NOLINTNEXTLINE
 #include <string>
 
+#include <rcpputils/scope_exit.hpp>
+
 #include "macros.h"
 #include "rcl_handle.h"
 #include "rcl_utilities.h"

src/rcl_subscription_bindings.cpp

@@ -19,10 +19,10 @@
 
 #include <cstdio>
 #include <memory>
-#include <rcpputils/scope_exit.hpp>
-// NOLINTNEXTLINE
 #include <string>
 
+#include <rcpputils/scope_exit.hpp>
+
 #include "macros.h"
 #include "rcl_handle.h"
 #include "rcl_utilities.h"

src/rcl_utilities.cpp

@@ -21,10 +21,10 @@
 
 #include <cstdio>
 #include <memory>
-#include <rcpputils/scope_exit.hpp>
-// NOLINTNEXTLINE
 #include <string>
 
+#include <rcpputils/scope_exit.hpp>
+
 namespace {
 
 const rmw_qos_profile_t* GetQoSProfileFromString(const std::string& profile) {