session.RenewPeriodic description is unclean

#### Overview of the Issue

https://github.com/hashicorp/consul/blob/87f6617eecd23a64add1e79eb3cd8dc3da9e649e/api/session.go#L164

Description of RenewPeriodic says that it is renewing a long-running session. But it is incorrect because it is also DESTROY session if doneCh is closed. It leads to a lot of confusion if you assume to reuse the session later.

https://github.com/hashicorp/consul/blob/87f6617eecd23a64add1e79eb3cd8dc3da9e649e/api/session.go#L201

#### Reproduction Steps

For example, we have multiple go routines running RenewPeriodic that following each other. I expect that the last routine will keep the session until TTL expired. If the session is required, then we renew the session ID. If not, then Consul will delete all resources after a while.

### Consul info

```
build:
prerelease =
revision = ca5c3894
version = 1.9.1
```

### Proposal

Is it possible to fix Golang description or add a boolean flag indicating whether Consul should delete the session or not?