workspace: fix span extraction with length of 1

[PabstMirror]

fixes
if (true) then { a } else { b };

push true
callFunction if;
push [{},{}]
callOperator then

I couldn't find any examples of the warn triggering, so I don't see any harm in adding it

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 68.3%. Comparing base (3c142e1) to head (b2c4518).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
libs/workspace/src/reporting/processed.rs	50.0%	1 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
libs/workspace/src/reporting/processed.rs	89.0% <50.0%> (-0.9%)	⬇️