if anyone is interested what I did was editing the

.idea/MY_PROJECT.iml

And added after the

<orderEntry type="sourceFolder" forTests="false" />

line that should be in that file the following snippet:

<orderEntry type="module-library">
      <library name="SuiteScript 2.0">
        <CLASSES>
          <root url="jar://$APPLICATION_PLUGINS_DIR$/com.netsuite.ide.webstorm.app/lib/com.netsuite.ide.webstorm.app_2018.2.0.jar!/library/SuiteScript_2_0" />
        </CLASSES>
        <SOURCES />
      </library>
    </orderEntry>