Several Minor Updates on Examples

[Indrazar]

• Added a button to errors_axum example to generate a 500 error with a <Form>
• Correct README.md on errors_axum example
• Ran clippy on errors_axum and todo_app_sqlite_axum examples

cargo clippy --no-deps --features="csr"
cargo clippy --no-deps --features="ssr"
cargo clippy --no-deps --features="hydrate"

• Changed a few cfg_if blocks to help rust_analyzer code completion
• Added "http://" to log so the page can be directly opened from the terminal when server starts

[gbj]

The CI runs cargo fmt --check before running tests, and it failed — could you cargo fmt and push the changes?

[requaos]

@gbj given the failure for note: /usr/bin/ld: final link failed: No space left on device will this ever pass? can we give the test runner more disk?

[gbj]

@requaos This has happened occasionally in the past; I'm surprised it's started occurring again. I generally finish running the CI on my computer, which is not ideal but is fine. I had changed a GitHub setting immediately before this happened and have reverted it... It may have been related.