use from table to remove into-db command

[elferherrera]

Description

Change db command from to from table to eliminate the need to use into db when using db commands.
into db is used as type hint for the parser to understand that the next commands that will be used are the db commands and not the regular nu commands

Examples
Before

open db.sqlite
| into db
| from table_1
| select a
| as t1

Suggested change

open db.sqlite
| from table table_1
| select a
| as t1

Note. Also the name of the test file was changed from db.mysql to db.sqlite to better represent what type of files are being opened

Tests

Make sure you've done the following:

• Add tests that cover your changes, either in the command examples, the crate/tests folder, or in the /tests folder.
• Try to think about corner cases and various ways how your changes could break. Cover them with tests.
• If adding tests is not possible, please document in the PR body a minimal example with steps on how to reproduce so one can verify your change works.

Make sure you've run and fixed any issues with these commands:

• cargo fmt --all -- --check to check standard code formatting (cargo fmt --all applies these changes)
• cargo clippy --workspace --features=extra -- -D warnings -D clippy::unwrap_used -A clippy::needless_collect to check that you're using the standard code style
• cargo test --workspace --features=extra to check that all the tests pass

[rgwood]

Thanks for fixing the examples!