startup/bootstrap: provide type signature

Library/Homebrew/startup/bootstrap.rbi

@@ -0,0 +1,28 @@
+# typed: strict
+
+module Bootsnap
+  sig {
+    params(
+      cache_dir:          String,
+      development_mode:   T::Boolean,
+      load_path_cache:    T::Boolean,
+      ignore_directories: T.nilable(T::Array[String]),
+      readonly:           T::Boolean,
+      revalidation:       T::Boolean,
+      compile_cache_iseq: T::Boolean,
+      compile_cache_yaml: T::Boolean,
+      compile_cache_json: T::Boolean,
+    ).void
+  }
+  def self.setup(
+    cache_dir:,
+    development_mode: true,
+    load_path_cache: true,
+    ignore_directories: nil,
+    readonly: false,
+    revalidation: false,
+    compile_cache_iseq: true,
+    compile_cache_yaml: true,
+    compile_cache_json: true
+  ); end
+end