Dump the 'using' options for a SQL index into the schema.

This was extracted from: #9944 / #8430 to only contain the functionality to dump the `using` option into the schema file.

In reviewing this I noticed that adding the `algorithm` SQL index options, #9923, did not include the algorithm in the schema dumper.  I think it probably should include it in the schema.  If you want me to make another pull request to add this functionality, let me know, I'd be happy to do so.

@rafaelfranca will you take a look at this?