Docs(Queue): Fix a PriorityQueue API missing bug

[DjangoPeng]

As we all know there are 4 subclass of class QueueBase, but only 3 subclass(FIFOQueue, PaddingFIFOQueue, RandomShuffleQueue) descriptions in the API Docs here

So I add the description of class PriorityQueue() which are the comments in ../python/ops/data_flow_ops.py.
Start line 714 to 759 and you can check here

[teamdandelion]

Thanks for the pull request! Unless I'm much mistaken, these files should be autogenerated from the source in data_flow_ops. @josh11b can you comment on what the right fix is?

[tensorflow-jenkins]

Can one of the admins verify this patch?

[josh11b]

The source for the documentation of tf.PriorityQueue lives in https://github.com/tensorflow/tensorflow/blob/master/tensorflow/python/ops/data_flow_ops.py#L715

tensorflow/g3doc/api_docs/python/io_ops.md is automatically generated. Any changes to it will be overwritten the next time the documentation generator runs. In fact, its very first line is:

The fact that PriorityQueue is not being generated is an issue, which we can hopefully fix by adding PriorityQueue to the list here:
https://github.com/tensorflow/tensorflow/blob/master/tensorflow/python/ops/io_ops.py#L82
(And hopefully then the doc generator will generate docs from the data_flow_ops.py file -- see https://www.tensorflow.org/versions/r0.10/how_tos/documentation/index.html for instructions on how to run the doc generator yourself. TL/DR: tools/docs/gen_docs.sh)

If, once the documentation is being generated, there are still improvements to be made, those changes should be made to data_flow_ops.py.

[DjangoPeng]

@josh11b So it is a missing mistake of the list, and when could you run the doc generator script?
And do you mean I don't need to push this commits this time?

[rmlarsen]

@DjangoPeng @josh11b I think Josh's point was that if you add the correct entry to

https://github.com/tensorflow/tensorflow/blob/master/tensorflow/python/ops/io_ops.py#L82

then the documentation will get automatically generated (visibility pending our push). Please go ahead and make that change as well as any documentation updates to data_flow_ops.py in this PR.

[DjangoPeng]

@rmlarsen I have added PriorityQueue into the list, plz check

[rmlarsen]

@DjangoPeng Can you please revert the changes from io_ops.md, since this is an autogenerated file, and instead update the documentation in

https://github.com/tensorflow/tensorflow/blob/master/tensorflow/python/ops/data_flow_ops.py#L715

if needed.

[DjangoPeng]

@rmlarsen I have reverted the change from io_ops.md, and it's unnecessary to update the data__flow_ops.py this time. Plz check.

[rmlarsen]

@tensorflow-jenkins test this please