Update time docs to reflect new chrono feature flag name

[willshiao]

Changes chrono -> chrono-04 to reflect the new name for the feature flag. This was confusing when I was trying to find the feature flag.

Pre-review checklist

• I have split my patch into logically separate commits.
• All commit messages clearly explain what they change and why.
• I added relevant tests for new features and bug fixes.
• All commits compile, pass static checks and pass test.
• PR description sums up the changes and reasons why they should be introduced.
• I have provided docstrings for the public items that I want to introduce.
• I have adjusted the documentation in ./docs/source/.
• I added appropriate Fixes: annotations to PR description.

[github-actions]

cargo semver-checks found no API-breaking changes in this PR! 🎉🥳
Checked commit: af69a1d

[wprzytula]

I believe we need to check other features in this aspect, because there are more that has been recently suffixed with a major version number and the docs might have fallen behind.

[muzarski]

I believe we need to check other features in this aspect, because there are more that has been recently suffixed with a major version number and the docs might have fallen behind.

True. I've found suspects in following files:

• date.md
• time.md
• timestamp.md

We should rename chrono -> chrono-04 and time -> time-03 in these files. @willshiao could you adjust all of these?

I see that bigdecimal-04, num-bigint-03 and num-bigint-04 features are documented correctly.

[willshiao]

Just made the requested name changes. I searched for occurrences of `time` or `chrono` in Markdown files so I should've gotten all of them but lmk if I missed any

[muzarski]

looks good

[Lorak-mmk]

I've started the CI and will merge after it passes.