Document exec chain behaviour when automatic retries are enabled.

[cachescrubber]

Document classic and async exec chain behaviour when automatic retries are enabled.

https://issues.apache.org/jira/browse/HTTPCLIENT-2291

[ok2c]

@cachescrubber Awesome! One thing, though. Do you mind dropping code snippets out of Javadocs, as code examples often tend to get out of sync with the actual API usage.

[cachescrubber]

@ok2c I removed the snippets. Having implemented a handler myself I remember having to dig in the source of clientBuilder in order to find the name of the retry handler. What about

 * @see ChainElement#RETRY
 * @see HttpClientBuilder#addExecInterceptorAfter(String, String, ExecChainHandler)
 * @see HttpClientBuilder#addExecInterceptorBefore(String, String, ExecChainHandler)

I think I would at least document the name (ChainElement#RETRY) in order to place the interceptors relative to it. WDYT?

[ok2c]

I think I would at least document the name (ChainElement#RETRY) in order to place the interceptors relative to it. WDYT?

Makes perfect sense.