Add type signatures to `Utils::Shebang`.

Library/Homebrew/utils/shebang.rb

@@ -6,14 +6,19 @@ module Utils
   #
   # @api private
   module Shebang
+    extend T::Sig
+
     module_function
 
     # Specification on how to rewrite a given shebang.
     #
     # @api private
     class RewriteInfo
+      extend T::Sig
+
       attr_reader :regex, :max_length, :replacement
 
+      sig { params(regex: Regexp, max_length: Integer, replacement: T.any(String, Pathname)).void }
       def initialize(regex, max_length, replacement)
         @regex = regex
         @max_length = max_length
@@ -27,6 +32,7 @@ module Utils
     #   rewrite_shebang detected_python_shebang, bin/"script.py"
     #
     # @api public
+    sig { params(rewrite_info: RewriteInfo, paths: T::Array[T.any(String, Pathname)]).void }
     def rewrite_shebang(rewrite_info, *paths)
       paths.each do |f|
         f = Pathname(f)