style: fix lint and remove unused file

Author: vkarpov15

lib/document.js

@@ -22,7 +22,6 @@ const cleanModifiedSubpaths = require('./helpers/document/cleanModifiedSubpaths'
 const compile = require('./helpers/document/compile').compile;
 const defineKey = require('./helpers/document/compile').defineKey;
 const flatten = require('./helpers/common').flatten;
-const flattenObjectWithDottedPaths = require('./helpers/path/flattenObjectWithDottedPaths');
 const get = require('./helpers/get');
 const getEmbeddedDiscriminatorPath = require('./helpers/document/getEmbeddedDiscriminatorPath');
 const getKeysInSchemaOrder = require('./helpers/schema/getKeysInSchemaOrder');