feat(attach): Support `--first` option for `attach` sub-command to let zellij choose the alphabetically first session; resolve#823
fix(attach-first): Fix `--first` option to choose the first created session in the existent sessions
feat(attach): Support `--index` option to choose the session indexed by provided number like -t option of tmux
feat(attach): Support listing active sessions with index when a provided number is not found in the active sessions
feat(attach): Support listing active sessions with index when a provided number is not found in the active sessions
feat: Add anyhow to uniformly treat error types and avoid panics
* feat(sessions): mirrored sessions
* fix(tests): input units
* style(fmt): make rustfmt happy
* fix(tests): make mirrored sessions e2e test more robust
* refactor(sessions): remove force attach
* style(fmt): rustfmtify
* docs(changelog): update change
* fix(e2e): retry on all errors
fixes#688
- the `options` subcommand of `attach` functions the same,
as the `options` subcommand of creating the normal session,
but not every option will have an effect on reattaching,
for example the `default_mode` setting would make no sense
to switch.
In the future it would make sense to be able to hot swap some
of the options on reattach, but we are not able to do that yet,
for example the `default_shell` one.
Eg:
```
zellij attach <session-name> options --theme <theme>
```
