SOLR-13309: Simplify references numeric-range classes

[gerlowskija]

Description

Prior to this commit, the org.apache.solr.schema.numericrange subpackage was not in the list of packages that SolrResourceLoader uses to support the "shorthand" class syntax. As a result, references to these classes had to use fully-qualified syntax
('org.apache.solr.schema.numericRange.IntLongField'), or semi-qualified ('solr.numericrange.IntLongField'). This was quite awkward.

Solution

This commit adds the 'numericrange' subpackage to the special list used by SRL, and cleans up the references to these field types to use the preferred shorthand syntax.

No changelog entry is needed for this change since these field types haven't been released yet so there's no "change" here from a user's perspective.

Tests

Additional numeric-range field tests continue to pass. No new tests added.

Checklist

Please review the following and check all that apply:

• I have reviewed the guidelines for How to Contribute and my code conforms to the standards described there to the best of my ability.
• I have created a Jira issue and added the issue ID to my pull request title.
• I have given Solr maintainers access to contribute to my PR branch. (optional but recommended, not available for branches on forks living under an organisation)
• I have developed this patch against the main branch.
• I have run ./gradlew check.
• I have added tests for my changes.
• I have added documentation for the Reference Guide

[gerlowskija]

Note to self that 'test' and 'check' pass locally for me. Will aim to merge this EOW and then close out SOLR-13309 pending any review feedback.

[HoustonPutman]

Looks great!