Remove View.enable_fts()

The method existed only to raise NotImplementedError, since
full-text search is not supported for views, and it showed up in
the generated API reference as a documented View method. Calling
enable_fts() on a View now raises AttributeError like any other
missing method. The sqlite-utils enable-fts command uses db.table()
and shows a clean error when pointed at a view instead of a
traceback.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UnLnhsH25Nnv7LHhekUfPd

sqlite_utils/cli.py

@@ -702,14 +702,14 @@ def enable_fts(
     _register_db_for_cleanup(db)
     _load_extensions(db, load_extension)
     try:
-        db[table].enable_fts(
+        db.table(table).enable_fts(
             column,
             fts_version=fts_version,
             tokenize=tokenize,
             create_triggers=create_triggers,
             replace=replace,
         )
-    except OperationalError as ex:
+    except (NoTable, OperationalError) as ex:
         raise click.ClickException(str(ex))