jsguide: Add recommendation rule - combine tags

https://google.github.io/styleguide/jsguide.html#jsdoc-tags

There is no hard rule for when to combine tags, or in which order, but be consistent.

- Why not have a recommendation like below?
- Have the 'combine' tags in alphabetical order, except that "export" & "import" must appear first
- Otherwise many tags in a line, without order, will create duplicates