Add RBS type signatures for Logger and generate RBS file

Steepfile

@@ -17,6 +17,7 @@ target :lib do
   check "lib/lrama/counterexamples.rb"
   check "lib/lrama/digraph.rb"
   check "lib/lrama/grammar.rb"
+  check "lib/lrama/logger.rb"
   check "lib/lrama/options.rb"
   check "lib/lrama/warning.rb"
 end

lib/lrama/logger.rb

@@ -1,15 +1,19 @@
+# rbs_inline: enabled
 # frozen_string_literal: true
 
 module Lrama
   class Logger
+    # @rbs (IO out) -> void
     def initialize(out = STDERR)
       @out = out
     end
 
+    # @rbs (String message) -> void
     def warn(message)
       @out << message << "\n"
     end
 
+    # @rbs (String message) -> void
     def error(message)
       @out << message << "\n"
     end

sig/generated/lrama/logger.rbs

@@ -0,0 +1,14 @@
+# Generated from lib/lrama/logger.rb with RBS::Inline
+
+module Lrama
+  class Logger
+    # @rbs (IO out) -> void
+    def initialize: (IO out) -> void
+
+    # @rbs (String message) -> void
+    def warn: (String message) -> void
+
+    # @rbs (String message) -> void
+    def error: (String message) -> void
+  end
+end