minimal requirement to use CGI.escapeHTML

[scivola]

We need to require only cgi/escape to use CGI.escapeHTML.

This change save memory usage about 265 KB and load time about ten milliseconds.

require "objspace"

GC.start
before = ObjectSpace.memsize_of_all
require "cgi"
after = ObjectSpace.memsize_of_all
puts "about %d KB" % ((after - before).fdiv(1024).round)
# => 269 KB

require "objspace"

GC.start
before = ObjectSpace.memsize_of_all
require "cgi/escape"
after = ObjectSpace.memsize_of_all
puts "about %d KB" % ((after - before).fdiv(1024).round)
# => 4 KB

(Ruby 2.7.0)

[agardiner]

Thanks for the PR, but unfortunately, this change does not work for older versions of Ruby, which are still a target for this project.

[scivola]

How about this?
cgi/escape was introduced at Ruby 2.3.0.
cgi/utils is available instead of cgi/escape for older Ruby versions (even for Ruby 1.9).

cgi/utils is larger than cgi/escape, but is smaller than entire cgi.