doc update to clarify that negative lookbehind assertion for regex is not supported
doc update to clarify that negative lookbehind assertion for regex is
not supported

pabloferz/CodeMirror,dperetti/CodeMirror,pabloferz/CodeMirror,codio/CodeMirror,wingify/CodeMirror,codio/CodeMirror,pabloferz/CodeMirror,hackmdio/CodeMirror,nightwing/CodeMirror,dperetti/CodeMirror,nightwing/CodeMirror,wingify/CodeMirror,dperetti/CodeMirror,nightwing/CodeMirror,hackmdio/CodeMirror,wingify/CodeMirror,hackmdio/CodeMirror,codio/CodeMirror