Fix suggest query names for Completion suggestor.

[tell-k]

According to official documentation, Completion Suggester seems to be using correct prefix rather than text.

POST music/_search?pretty
{
    "suggest": {
        "song-suggest" : {
            "prefix" : "nir", 
            "completion" : { 
                "field" : "suggest" 
            }
        }
    }
}

In the Search.suggest method, however, it always becomes text, so I fixed it.

In Completion Suggestor you can also specify regex.

POST music/_search?pretty
{
    "suggest": {
        "song-suggest" : {
            "regex" : "n[ever|i]r",
            "completion" : {
                "field" : "suggest"
            }
        }
    }
}

I also modified it so that the user can select it.

# Sample of use

# Term Suggester
s = s.suggest('song-suggest', 'nir', term={'field': 'suggest'})

# Completion Suggester + prefix query
s = s.suggest('song-suggest', 'nir', completion={'field': 'suggest'})

# Completion Suggester + regex query
s = s.suggest('song-suggest', regex='n[ever|i]r', completion={'field': 'suggest'})
# "regex"  must be keyword argument.

Please feel free to merge it. thx.

[tell-k]

@honzakral

Is there any problem with this PR?
If there are problems, I'll fix them.

thx :)

[honzakral]

Thank you for the PR, and for the ping. Nothing wrong with the PR except for my lack of time :)

I added a short comment where I think we can do a bit better for easier code, if you agree then we can merge the PR.

[honzakral]

I think we need additional validation rules here - if you supply both text and regex or you supply regex and completion is not in kwargs etc - any invalida combination essentially should raise a ValueError.

[tell-k]

OK, i'll fix it more strictly.

[honzakral]

once we have validated out all the invalid combinations we should be ok with simpler code:

d = s._suggest[name] = kwargs
if text:
    d['text'] = text
else:
    d['regex'] = regex

[tell-k]

@honzakral

Thank you for your review.
I fixed the points pointed out by you.
Please feel free to review it again.

I pray that you can afford the time :)

[tell-k]

@honzakral

Can you review this PR again ?
If there's anything I can do for you, please let me know. Thx :)

[tell-k]

@honzakral Any chance you can review and merge this?

[sethmlarson]

Closing this PR as it's gone stale, rebase on master and I'll review again