Enforce stricter requirements for Editor.getPane()
Enforce stricter requirements for Editor.getPane()

Previously it would return the closest '.pane' element
which would cause an editor inside of another editor
to report having a pane such as in the autocomplete view.

adamCoGithub/Bracket-Matcher-no-smart-quotes,jacekkopecky/bracket-matcher,jacekkopecky/bracket-matcher,lpommers/bracket-matcher,lpommers/bracket-matcher,adamCoGithub/Bracket-Matcher-no-autoclose,bwinton/bracket-matcher,adamCoGithub/Bracket-Matcher-no-autoclose,bwinton/bracket-matcher,adamCoGithub/Bracket-Matcher-no-smart-quotes,atom/bracket-matcher