Update h2 and servo-tidy.toml (#30948)

Cargo.lock

@@ -2567,9 +2567,9 @@ checksum = "b1334b94d8ce67319ddc44663daef53d8c1538629a11562530c981dbd9085b9a"
 
 [[package]]
 name = "h2"
-version = "0.3.21"
+version = "0.3.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "91fc23aa11be92976ef4729127f1a74adf36d8436f7816b185d18df956790833"
+checksum = "4d6250322ef6e60f93f9a2162799302cd6f68f79f6e5d85c8c16f14d1d958178"
 dependencies = [
  "bytes",
  "fnv",
@@ -2577,7 +2577,7 @@ dependencies = [
  "futures-sink",
  "futures-util",
  "http",
- "indexmap 1.9.3",
+ "indexmap 2.1.0",
  "slab",
  "tokio",
  "tokio-util",

servo-tidy.toml

@@ -28,6 +28,8 @@ packages = [
     "nix",
     "num-rational",
     "redox_syscall",
+    "syn",
+    "synstructure",
     "time",
     "wasi",
     "wayland-sys",
@@ -52,16 +54,14 @@ packages = [
     "foreign-types-shared",
     "metal",
     "paste",
-    # Duplicated by gpu-descriptor and indexmap
+
+    # Duplicated by indexmap.
     "hashbrown",
-    # Duplicated by script, style, cbindgen, clap, ...
+
+    # Duplicated by style, cbindgen, clap.
     "indexmap",
 
-    # Duplicated by Gecko crates that haven't been updated yet (style, shmem, derive_common, ...).
-    "syn",
-    "synstructure",
-
-    # style/webxr (0.62) vs. mozjs_sys (0.66)
+    # style (0.64) vs. webxr (0.66) vs. mozjs_sys (0.68).
     "bindgen",
 ]
 # Files that are ignored for all tidy and lint checks.