Add formatting infrastructure to the project.

Add infrastructure to format c++ files with clang-format.
We require clang-format-18 because some of the clang-format options
we're using have only been released with clang-format 18.
General project llvm version required remains unchanged.
Added:
1. clang-format file matching internal one
2. formatting tool based on python for cross-platform
3. pre-commit and pre-push hooks for formatting validation
4. Lint CI action.

src/workerd/api/sockets.c++

@@ -425,8 +425,7 @@ void Socket::handleReadableEof(jsg::Lock& js, jsg::Promise<void> onEof) {
   KJ_ASSERT(!getAllowHalfOpen(options));
   // Listen for EOF on the ReadableStream.
   onEof
-      .then(
-          js,
+      .then(js,
           JSG_VISITABLE_LAMBDA(
               (ref = JSG_THIS), (ref), (jsg::Lock& js) { return ref->maybeCloseWriteSide(js); }))
       .markAsHandled(js);

src/workerd/tests/bench-tools.h

@@ -13,15 +13,14 @@
 // enough to not need ns precision.
 #define WD_BENCHMARK(X) BENCHMARK(X)->Unit(benchmark::kMicrosecond)
 
-/* Macro inspired by KJ_TEST() to enable benchmarking without requiring the benchmark::State */                                            \
-/* argument and make it easy to convert tests to benchmarks. */ /* Make sure the linker fails if tests are not in anonymous namespaces. */ \
-#define WD_BENCH(description)                                                                                                              \
-  extern int KJ_CONCAT(YouMustWrapTestsInAnonymousNamespace, __COUNTER__) KJ_UNUSED;                                                       \
-  void KJ_UNIQUE_NAME(Bench)();                                                                                                            \
-  void KJ_UNIQUE_NAME(BenchImpl)(benchmark::State & state) {                                                                               \
-    for (auto _: state) {                                                                                                                  \
-      KJ_UNIQUE_NAME(Bench)();                                                                                                             \
-    }                                                                                                                                      \
-  }                                                                                                                                        \
-  WD_BENCHMARK(KJ_UNIQUE_NAME(BenchImpl))->Name(description);                                                                              \
+/* Macro inspired by KJ_TEST() to enable benchmarking without requiring the benchmark::State */ /* argument and make it easy to convert tests to benchmarks. */ /* Make sure the linker fails if tests are not in anonymous namespaces. */ \
+#define WD_BENCH(description)                                                                                                                                                                                                              \
+  extern int KJ_CONCAT(YouMustWrapTestsInAnonymousNamespace, __COUNTER__) KJ_UNUSED;                                                                                                                                                       \
+  void KJ_UNIQUE_NAME(Bench)();                                                                                                                                                                                                            \
+  void KJ_UNIQUE_NAME(BenchImpl)(benchmark::State & state) {                                                                                                                                                                               \
+    for (auto _: state) {                                                                                                                                                                                                                  \
+      KJ_UNIQUE_NAME(Bench)();                                                                                                                                                                                                             \
+    }                                                                                                                                                                                                                                      \
+  }                                                                                                                                                                                                                                        \
+  WD_BENCHMARK(KJ_UNIQUE_NAME(BenchImpl))->Name(description);                                                                                                                                                                              \
   void KJ_UNIQUE_NAME(Bench)()