Make #strip_color only remove colors.

The previous implementation was removing more than that. When Pry.color = false, it was messing up the output of a few commands.

lib/pry/helpers/text.rb

@@ -44,7 +44,7 @@ class Pry
       # @param  [String, #to_s] text
       # @return [String] _text_ stripped of any color codes.
       def strip_color(text)
-        text.to_s.gsub(/(\001)?\e\[.*?(\d)+m(\002)?/, '')
+        text.to_s.gsub(/(\001)?(\e\[(\d[;\d]?)*m)(\002)?/, '')
       end
 
       # Returns _text_ as bold text for use on a terminal.

spec/helpers/text_spec.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+describe Pry::Helpers::Text do
+  describe "#strip_color" do
+    [
+      ["\e[1A\e[0G[2] pry(main)> puts \e[31m\e[1;31m'\e[0m\e[31m"\
+         "hello\e[1;31m'\e[0m\e[31m\e[0m\e[1B\e[0G",
+       "\e[1A\e[0G[2] pry(main)> puts 'hello'\e[1B\e[0G"],
+      ["\e[31m\e[1;31m'\e[0m\e[31mhello\e[1;31m'\e[0m\e[31m\e[0m\e[1B\e[0G",
+       "'hello'\e[1B\e[0G"],
+      %w[string string]
+    ].each do |(text, text_without_color)|
+      it "removes color code from text #{text.inspect}" do
+        expect(subject.strip_color(text)).to eql(text_without_color)
+      end
+    end
+  end
+end