add style team triagebot config

triagebot.toml

@@ -456,6 +456,9 @@ These commits modify **compiler targets**.
 (See the [Target Tier Policy](https://doc.rust-lang.org/nightly/rustc/target-tier-policy.html).)
 """
 
+[mentions."src/doc/style-guide"]
+cc = ["@rust-lang/style"]
+
 [assign]
 warn_non_default_branch = true
 contributing_url = "https://rustc-dev-guide.rust-lang.org/contributing.html"
@@ -560,6 +563,12 @@ ast_lowering = [
 fallback = [
     "@Mark-Simulacrum"
 ]
+style-team = [
+    "@calebcartwright",
+    "@compiler-errors",
+    "@joshtriplett",
+    "@yaahc",
+]
 
 [assign.owners]
 "/.github/workflows" =                       ["infra-ci"]
@@ -604,6 +613,7 @@ fallback = [
 "/src/doc/rust-by-example" =                 ["@ehuss"]
 "/src/doc/rustc-dev-guide" =                 ["@ehuss"]
 "/src/doc/rustdoc" =                         ["rustdoc"]
+"/src/doc/style-guide" =                     ["style-team"]
 "/src/etc" =                                 ["@Mark-Simulacrum"]
 "/src/librustdoc" =                          ["rustdoc"]
 "/src/llvm-project" =                        ["@cuviper"]