I did a bad thing and pushed patches to master then cut a release of
`bitcoind-json-rpc-client` without using a PR, and forgot to update lock
files - so here it is.

Its "features" not "feadures", fix multiple instances of the typo.

The readme is stale because it is the one we grabbed when importing
`bitcoind`. Since this crate is currently being release under a
different name remove the stale docs that are specific to `bitcoind`.

The crate is not typical in that it expects at least one of the "verison
number" features to be enabled. This does not play nicely with the
docs.rs build. In an effort to make things at least uderstandable add do
a few things:

- inline the `Client` and `json` docs
- configure docs.rs build to enable 26_0
- Add a big fat note to hopefully alleviate the misleading
  "Available on crate feature 26_0 only."

In preparation for doing a point release bump the version and add a
changelog.