Do not output unneeded escapes

[wooorm]

Subject of the feature

Escaping happens on characters, including what comes right before and after them. One example is if ![a](b) was found in a text node, which has to be made safe so it doesn’t turn into something else.

Problem

The bang before the left bracket, the left bracket, and the left paren, are all escaped. In the first case because it precedes a bracket, in the last case because it follows a bracket, and in the opening bracket’s case, because well, they cause lots of stuff to happen.

Expected behavior

All three is superfluous. The square bracket and paren seem wise?

[wooorm]

Another example right now:

carbon.now.sh gets transformed to carbon.now\.sh. Why???!

(edit: because it might turn into a URL otherwise, do’h)