Rename doc event

[kyleknap]

This PR switches the event_class for the the various operation objects. A big problem with the current event_class attributes was that the values varied widely and were not consistent across help commands.

For example, the values varied from Provider to Operation to an abreviation to a service and even just a straight command for the custom commands.

I switched it so that the event classes rely on a command's lineage for event_class with the names of the commands in the lineage delimited by periods here are some examples:

• aws ec2 help --> ec2
• aws s3 cp --> s3.cp
• aws s3api wait object-exists --> s3api.wait.object-exists

The end event name that bcdoc fires looks a little weird in the end because bcdoc makes assumptions on how the event_class is formatted. I can make a subsequent pull request to fix that.

However by using this format in event_class it does several things for us:

1. All of the breadcrumbs are fixed. Here are some before and after pictures of some commands:

before (no breadcrumb):

after (breadcrumb is there):

before (custom commands had weird names):

after (name is corrected):

before (waiters missed some of the commands):

after (all commands are included):

2. Allow us to use :ref: syntax throughout the cli documentation. I added a reference label to the top of
   each reference documentation title. The labels take the form of .. _aws [command] ...:. This allows you to reference the command using the sphynx :ref: syntax which I switched the breadcrumbs to use.

Note that there are 4 commits in this PR. The first two are directly from this PR: #1148. So you do not need to look at those changes for this PR, just for the other PR.

cc @jamesls @danielgtaylor

[coveralls]

Coverage decreased (-0.06%) to 91.86% when pulling 14d4203 on kyleknap:rename-doc-event into 435f655 on aws:develop.

[coveralls]

Coverage increased (+0.08%) to 92.0% when pulling 14d4203 on kyleknap:rename-doc-event into 435f655 on aws:develop.

[kyleknap]

Coverage report looks fine despite comment

[jamesls]

I think we should get the bcdoc event names updated before merging this. I'd rather avoid having changes such as: https://github.com/aws/aws-cli/pull/1151/files#diff-10d9faf99f1b18c865fd1aebf80d163bR26 which should be unnecessary once we fix the bcdoc event names.

[kyleknap]

So these tests will fail until this bcdoc PR is merged in: boto/bcdoc#33

In addition, I made a change to how I do the bread crumbs and references at the top of section headers. I made the change such that they are prefixed by cli:. This helped avoid collisions with references created from docs in the JSON model. There were a few aws <servicename> references in the models.

Otherwise it is ready to be looked at for both PR's.
@jamesls @danielgtaylor

[jamesls]

Let's get a clean run through travis after the bcdoc merge. Otherwise looks good.

[coveralls]

Coverage decreased (-0.05%) to 91.86% when pulling 7add479 on kyleknap:rename-doc-event into 768b2a8 on aws:develop.

[coveralls]

Coverage increased (+0.09%) to 92.0% when pulling 7add479 on kyleknap:rename-doc-event into 768b2a8 on aws:develop.

[kyleknap]

Test pass with bcdoc merge.

Coverage stayed the same or increased for files I had changed. Only the s3 tasks.py decreased, which has been happening for most cli pull request, and my changes should not have affected it at all.

Merging otherwise.