Merge metadata updates from upstream r556
Generated Python files for metadata
Fix space position
Use the package-level versions of geocoder functions
Test all geocoder entrypoints directly
Remove errant @@
Do load-on-demand for geocoder entrypoints.

The geocoding metadata is large, and many library
users don't use it, so only load it (by doing
import .geocoder) if it's needed.
Copy docstrings for wrapped geocoder functions
Add & use PhoneMetadata.metadata_for_region accessor
Add & use PhoneMetadata.metadata_for_nongeo_region accessor
Use accessors in metadata_for_region_or_calling_code
Add on-demand loader mechanism for metadata
Use common REGION_CODE_FOR_NON_GEO_ENTITY
Confirm use of int for nongeo key type
Move tests to use accessors
Test metadata needs to replace loaders too
Generate on-demand loaders for metadata
Regenerated metadata masters, using on-demand loaders
Underscore-prefix internal class variables.
Add method to force immediate load of metadata