docs/gql: code sample doesn't parse

[alxndrsn]

The second code sample at https://pouchdb.com/gql.html reads:

const pouchdb;
PouchDB('idb://test', function(err, db) {
   pouchdb = db;
  // Use pouchdb to call further functions
    db.gql({select: "*", where: "type='Fire' and name is not null"}, function(err, result){
        if(!err){
        // Use the results of the query here
        }
      }
})