Update readme with current CLI help results

[roblabs]

This PR updates README with what the CLI currently is reporting back to the user. The Swift ArgumentParser is highlighted so that users can know that there is decent CLI help via mvt help <subcommand>.

1. Update readme with current CLI help results
2. Add example of mvt info

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Sample mvt info for the .pbf stored in ~/Tests/

Name               | Features | Points | LineStrings | Polygons | Unknown | Version
--------------------+----------+--------+-------------+----------+---------+--------
admin              | 0        | 0      | 0           | 0        | 0       | 2      
aeroway            | 0        | 0      | 0           | 0        | 0       | 2      
airport_label      | 0        | 0      | 0           | 0        | 0       | 2      
area_label         | 55       | 55     | 0           | 0        | 0       | 2      
barrier_line       | 4219     | 0      | 4219        | 0        | 0       | 2      
bridge             | 14       | 0      | 14          | 0        | 0       | 2      
building           | 5414     | 0      | 0           | 5414     | 0       | 2      
building_label     | 413      | 413    | 0           | 0        | 0       | 2      
country_label      | 0        | 0      | 0           | 0        | 0       | 2      
country_label_line | 0        | 0      | 0           | 0        | 0       | 2      
landuse            | 206      | 0      | 0           | 206      | 0       | 2      
landuse_overlay    | 4        | 0      | 0           | 4        | 0       | 2      
marine_label       | 0        | 0      | 0           | 0        | 0       | 2      
place_label        | 1        | 1      | 0           | 0        | 0       | 2      
rail_station_label | 2        | 2      | 0           | 0        | 0       | 2      
road               | 502      | 1      | 497         | 4        | 0       | 2      
road_label         | 309      | 0      | 309         | 0        | 0       | 2      
state_label        | 0        | 0      | 0           | 0        | 0       | 2      
tunnel             | 2        | 0      | 2           | 0        | 0       | 2      
water              | 18       | 0      | 0           | 18       | 0       | 2      
water_label        | 1        | 1      | 0           | 0        | 0       | 2      
waterway           | 71       | 0      | 71          | 0        | 0       | 2      
waterway_label     | 7        | 0      | 7           | 0        | 0       | 2      

[roblabs]

mvt info

Use mvt info on a vector tile from MapLibre World.

mvt info https://demotiles.maplibre.org/tiles/2/2/1.pbf

---

Result

Name      | Features | Points | LineStrings | Polygons | Unknown | Version
----------+----------+--------+-------------+----------+---------+--------
centroids | 104      | 104    | 0           | 0        | 0       | 2      
countries | 113      | 0      | 0           | 113      | 0       | 2      
geolines  | 4        | 0      | 4           | 0        | 0       | 2    

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[trasch]

Thank you, @roblabs ! Any documentation update is very much appreciated!

I wonder if I miss something, because I can't see the example output in the diff, only here in the PR? Would be a nice info, but I would probably then move the command line part a bit further down below the source code (and add an index on top?)

[roblabs]

@trasch — based on your feedback on #14 & #15, I have updated the README in this branch. Can you review and merge if you approve?

🎉