function parseMatchSection(input) {
  var parts = (input.context || '').split(' ');
  var last = parts.pop();
  var beforeLast = strip(parts[parts.length - 1] || '').trim();
  if (beforeLast.slice(0, 1) === '-') {
    input.option = beforeLast;
  }
  input.context = last;
  input.prefix = (input.prefix || '') + parts.join(' ') + ' ';
  return input;
}
Takes the context after a
matched command and figures
out the applicable context,
including assigning its role
such as being an option
parameter, etc.

@param {Object} input
@return {Object}
@api private