[metacling] Offer RLogger interface to trace autoparsing:

[Axel-Naumann]

It allows (e.g. CMS) to set

RLogScopedVerbosity debugThis(gInterpreter->PerfLog(), ELogLevel::kDebug + 1);

to trace invocations of the autoparsing (and only that).

[phsft-bot]

Starting build on ROOT-debian10-i386/cxx14, ROOT-performance-centos8-multicore/default, ROOT-fedora30/cxx14, ROOT-fedora31/noimt, ROOT-ubuntu16/nortcxxmod, mac1014/python3, mac11.0/cxx17, windows10/cxx14
How to customize builds

[pcanal]

Suggested change

	/// Access the log channel for observice performance-critical actions.
	/// Access the log channel for observe performance-critical actions.

[phsft-bot]

Build failed on windows10/cxx14.
Running on null:C:\build\workspace\root-pullrequests-build
See console output.

Errors:

• [2021-03-19T17:25:29.506Z] C:\build\workspace\root-pullrequests-build\root\roofit\RDataFrameHelpers\test\testActionHelpers.cxx(22,73): error C3493: 'nEvent' cannot be implicitly captured because no default capture mode has been specified [C:\build\workspace\root-pullrequests-build\build\roofit\RDataFrameHelpers\test\testActionHelpers.vcxproj]
• [2021-03-19T17:25:31.223Z] C:\build\workspace\root-pullrequests-build\root\roofit\RDataFrameHelpers\test\testActionHelpers.cxx(23,73): error C3493: 'nEvent' cannot be implicitly captured because no default capture mode has been specified [C:\build\workspace\root-pullrequests-build\build\roofit\RDataFrameHelpers\test\testActionHelpers.vcxproj]