Many resources use an invalid fhirpath constraint on the root element:

`name.matches('[A-Z]([A-Za-z0-9_]){0,254}')`

This is invalid because name is an optional field.  Thus, in the cases where `name` is empty, this evaluates to `{}` rather than `true`. 

Suggested fix: Move this constraint to the `name` field. 

Full list of affected r4 resources:

ActivityDefinition
EventDefinition
Evidence
RiskEvidenceSynthesis
EvidenceVariable
Questionnaire
ExampleScenario
Measure
CapabilityStatement
Library
EffectEvidenceSynthesis
ResearchDefinition
PlanDefinition
ResearchElementDefinition