JSDuck: Fix warnings

Warning: modules/ve/test/ve.qunit.js:5: Class QUnit not found
Warning: .docs/categories.json No class found matching a pattern 've.Position' in categories file
Warning: modules/ve/ce/ve.ce.Surface.js:1297: Unknown type MouseEvent
Warning: modules/ve/ce/ve.ce.Surface.js:1297: Unknown type int

Follows-up:
* Ic21c9d3f
* Ib521eaa6

Change-Id: I8e371a2d4d91a1f03bd4ef59d18b7df715f23238