The current `next` pre-command workaround on IRB source stepping
moves the location by 1 extra line. A better way is to make `debug`
skip IRB frames completely, which is what this commit does.
It also fixes the step command's test. The `|` in regexp was not escaped
so it was always incorrectly matched.
(https://github.com/ruby/irb/pull/449)
* Seamlessly integrate a few debug commands
* Improve the break command support
* Utilize skip_src option if available
* Add step and delete commands
* Write end-to-end tests for each debugger command
* Add documentation
* Add backtrace, info, catch commands
976100c1c2
(https://github.com/ruby/irb/pull/448)
* Minor fixes on debug command
* Discover and load debug.gem even if it's not in Gemfile
* Eliminate else for rescue
* Discover the latest one from all gem paths
