A non-existent materialized view raises an error telling you to create a table

Using this code when there's no view named `some_view`

```crystal
class MaterializedView < Avram::Model
view :some_view, materialized: true do
column name : String
end
end
```

you'll get this error

```
MaterializedView wants to use the 'some_view' table but it is missing.

If you need to create the 'some_view' table...

▸ Generate a migration:

lucky gen.migration CreateMaterializedView

▸ Create the table in the migration:

create table_for(MaterializedView) do/end

Or, you can skip schema checks for this model:

class MaterializedView < BaseModel
# Great for models used in migrations, or for legacy schemas
skip_schema_enforcer
end

(Avram::SchemaMismatchError)
from src/avram/schema_enforcer/ensure_existing_table.cr:24:9 in 'validate!'
from spec/avram/multi_database_spec.cr:49:3 in 'ensure_correct_column_mappings!'
from spec/avram/multi_database_spec.cr:101:7 in '->'
```

The error is a bit misleading since we're not trying to use a table here, it's a view... However, it's possible that the `view` could be the wrong thing 🤷‍♂️ So maybe we just need to say `wants to use the 'some_view' table/view`, etc..? Be generic about both? Or if it's possible to know which one is being tried, then say "view" when it's a view or "table" otherwise.

Start in src/avram/schema_enforcer/ensure_existing_table.cr, where the schema mismatch is raised, and inspect the view declaration and existing coverage around spec/avram/multi_database_spec.cr. Add a regression case for a missing materialized view and verify that the resulting message identifies a view or otherwise avoids incorrectly calling it a table.

Written by the indexing model from the issue text.