Add documentation to CSC and GEM digi dataformats

[dildick]

In this pull request:

• The conversion of (strip number, comparator reading) to halfstrip number is frequently done in the CSC trigger and DAQ step. The implementation here is based on the definition used in the function CSCCLCTData::add() in EventFilter/CSCRawToDigi.
• I added some extra documentation in the interface of CSC and GEM digi dataformats to clarify whether a strip/wire/pad counts from 0 or 1.

[cmsbuild]

A new Pull Request was created by @dildick (Sven Dildick) for CMSSW_8_1_X.

It involves the following packages:

DataFormats/CSCDigi

@cmsbuild, @civanch, @mdhildreth, @davidlange6 can you please review it and eventually sign? Thanks.
@ptcox this is something you requested to watch as well.
@slava77, @smuzaffar you are the release manager for this.

cms-bot commands are list here #13028

[civanch]

please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/14493/console

[cmsbuild]

+1
Tested at: ef3fc5e
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-15441/14493/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-15441/14493/summary.html

@slava77 comparisons for the following workflows were not done due to missing matrix map:

• 10424.0_TTbar_13+TTbar_13TeV_TuneCUETP8M1_2023D1_GenSimFull+DigiFull_2023D1+RecoFullGlobal_2023D1+HARVESTFullGlobal_2023D1

[civanch]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_8_1_X IBs (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @slava77, @davidlange6, @smuzaffar

[davidlange6]

+1