Support for key "lock_name"

[philippelatulippe]

Problem

Locks are tagged as regular waterways with an additional tag lock=yes. This means that their name tag is often simply the name of the river or canal, while the name of the lock itself is tagged in lock_name, as recommended in Key:lock. Nominatim doesn't see this tag, so these locks cannot be searched for by name.

Solution

Add the key lock_name to the list of tags that are considered names.

Alternatives

Couldn't think of any. Hopefully this is a straightforward solution.

Additional context

Searching for the name of a lock is useful not just for boaters, but also for regular folks who live in cities that have many of them, where they are often gathering places. The name of locks are also mentioned in the news and blogs posts, for instance the Weerdsluis which is often talked about internationally due to its 'fish doorbell'.