net/http: add doc details regarding Transport retries
Add doc details to Transport mentioning retries only occur if a connection
has been already been used successfully.
Change-Id: I37afbad50b885248e0e6cd5e799ad848bf97c86b
GitHub-Last-Rev:
7c45c32aec2bd3266c525bf28ab1879acbecf193
GitHub-Pull-Request: golang/go#51273
Reviewed-on: https://go-review.googlesource.com/c/go/+/386994
Run-TryBot: Damien Neil <dneil@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>