Default value expressions are returned incorrectly

Describe the Bug

Complex parameter default expressions (specifically those involving an AST branch node) are returned incorrectly.

For example:

class test($param = 1 + 1) { ... }

The default value for $param is returned as +.

Expected Behavior

The default value should be returned as 1 + 1.

Additional Context

This seems to happen because ParameterizedStatement parser uses a SourcePosAdapter from Puppet to extract the text for the AST object. However, the extract_text method it calls only extracts the text for the AST branch itself, not for the entire tree rooted in that branch. The SourcePosAdapter calls @object.locator.extract_text, but there is an extract_tree_text method available on the locator which seems to do the right thing.

https://github.com/puppetlabs/puppet-strings/blob/main/lib/puppet-strings/yard/parsers/puppet/statement.rb#L89-L90
https://github.com/puppetlabs/puppet/blob/master/lib/puppet/pops/adapters.rb#L63
https://github.com/puppetlabs/puppet/blob/master/lib/puppet/pops/parser/locator.rb#L55

I would file a PR but I'm not deep enough into puppet-strings to understand its relationship to Puppet and the compatibility issues involved with the SourcePosAdapter to know the appropriate place to make this change.

Read lib/puppet-strings/yard/parsers/puppet/statement.rb at lines 89-90, then compare Puppet's SourcePosAdapter and locator methods referenced in the issue. Trace how the default expression in class test($param = 1 + 1) is extracted; done means the returned value includes the full 1 + 1 expression without breaking Puppet compatibility.