Use stdio directly on "dumb" terminals

Resolves pry#2303

lib/pry/config.rb

@@ -153,7 +153,7 @@ class Config
 
     def initialize
       merge!(
-        input: MemoizedValue.new { lazy_readline },
+        input: MemoizedValue.new { choose_input },
         output: $stdout.tap { |out| out.sync = true },
         commands: Pry::Commands,
         prompt_name: 'pry',
@@ -286,7 +286,9 @@ def control_d_handler=(value)
 
     private
 
-    def lazy_readline
+    def choose_input
+      return InputStdioShim.new if Pry::Env['TERM'] == 'dumb'
+
       require 'readline'
       ::Readline
     rescue LoadError

lib/pry/config/input_stdio_shim.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class Pry
+  # Readline replacement for low-capability terminals.
+  class InputStdioShim
+    def readline(prompt)
+      $stdout.print(prompt)
+      $stdin.gets
+    end
+  end
+end