CxxUtils: Add standalone begin/end functions for span.

Add standalone begin/end functions for span. Works around issues seen when combining root 6.30.4 and gcc14.

This merge request affects 1 package:

• Control/CxxUtils

This merge request affects 1 file:

• Control/CxxUtils/CxxUtils/span.h

Adding @ssnyder as watcher

added Core main review-pending-level-1 labels

CI Result SUCCESS (hash cc29706e)

	Athena	AthSimulation	AthGeneration	AnalysisBase	AthAnalysis	DetCommon
externals
cmake
make
tests

Full details available on this CI monitor view. Check the JIRA CI status board for known problems
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
AthGeneration: number of compilation errors 0, warnings 0
AnalysisBase: number of compilation errors 0, warnings 0
AthAnalysis: number of compilation errors 0, warnings 0
DetCommon: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-EL9 5365] (remote access info)

removed review-pending-level-1 label

added review-approved label

merged

mentioned in commit a6026205