Ruby: fix some synchronization code in server implementation

Fix C# artifacts compatibility

Don't set linetrace unless testing coverage

Fixes #5561

Fix other typo to match previous typo fix.

Doc Fixit: src/cpp/README need more information

Conflicts:
	INSTALL.md
	examples/cpp/README.md

Release GIL in queue __dealloc__

Merge release-0_13 into master

Fix memory leak: keep all resolver calls under the same lock

Fix memory leak if call is already cancelled

Fix comparison direction - fixes timer_list_test flakiness

Fix typo

- Revised 'protoc' section and 'Documentation' section as LisaFC suggested.
- Added 'Examples' section as LisaFC suggested.

Resolves: #5661

Obvious in hindsight, if the cas failed, we still created the subchannel
call object and then left it dangling.

Fixes a leak observed on master in the past 48 hours.

Updated main examples README to link to main docs and quickstarts

Doc Fixit: Clarifying how to install for gRPC C++