fix: remove ReDoS regexp

[zhuangya]

• split the line by '\n',
• and trim each line(do we really need to trim each line?).
• then join each line by ' '

i think this is the same as the original RegExp, correct me if wrong.

fix #501

[coveralls]

Coverage increased (+2.1%) to 74.839% when pulling 42a6ae0 on zhuangya:redos into 47747f3 on visionmedia:master.

[coveralls]

Coverage increased (+2.1%) to 74.839% when pulling 42a6ae0 on zhuangya:redos into 47747f3 on visionmedia:master.

[coveralls]

Coverage increased (+2.1%) to 74.839% when pulling 42a6ae0 on zhuangya:redos into 47747f3 on visionmedia:master.

[TooTallNate]

Thank you!

[dougwilson]

Can this be backported to the 2.x series?

[TooTallNate]

@dougwilson Sure thing: https://github.com/visionmedia/debug/releases/tag/2.6.9

Curious what's holding you back from upgrading though 😅