Apply socketserver.h improvements from (original) #648

[rbergen]

Description

This applies the linguistic (natural language and C++) improvements to socketserver.h that were originally included in #648. I excluded them from that PR because I am not able to test them.

This means that as soon as someone can confirm they have seen the socket server fully working on at least one device and at least one configuration(/project/environment) with these changes applied, they can be merged also.

Contributing requirements

• [x] I read the contribution guidelines in CONTRIBUTING.md.
• [x] I understand the BlinkenPerBit metric, and maximized it in this PR.
• [x] I selected main as the target branch.
• [x] All code herein is subjected to the license terms in COPYING.txt.