Consistent with this FHIRPath tracker:
https://jira.hl7.org/browse/FHIR-36257

Clarify that the .matches() function uses partial match semantics, and give the following example:

define TestMatches: Matches('http://fhir.org/guides/cqf/common/Library/FHIR-ModelInfo|4.0.1', 'Library')
// returns true

The start/end of line markers `^`, `$` can be used to match the entire string.

```cql
'http://fhir.org/guides/cqf/common/Library/FHIR-ModelInfo|4.0.1'.matches('Library') // returns true
'N8000123123'.matches('^N[0-9]

{8}$') // returns false as the string is not an 8 char number (it has 10)
'N8000123123'.matches('N[0-9]{8}

') // returns true as the string has an 8 number sequence in it starting with `N`
```