consolidation of examples: date_time_functions

[logan-keede]

Which issue does this PR close?

• Closes [EPIC] Improve examples to make them easier to navigate #11172
• Part of [Epic] Better / Improved Documentation, Tutorials and Examples #7013.

Rationale for this change

All functions are related to date_time functionality, it is easier to navigate if they are together.
assertions allow us to view expected output without running, can also serve as partial tests.
as mentioned in #13939 by @comphead

What changes are included in this PR?

Are these changes tested?

No. just examples.

Are there any user-facing changes?

No.

[logan-keede]

cc @alamb @comphead

[comphead]

Thanks @logan-keede triggering the run

[alamb]

Thank you @logan-keede -- this looks like a great improvement to me ❤️

FYI @Omega359 as I think you contributed many of these examples originally

[comphead]

thanks @logan-keede for removing also to_char.rs I doubled checked it and it refers to conversion from dates so it perfectly fits to date and time examples

[logan-keede]

thanks @logan-keede for removing also to_char.rs I doubled checked it and it refers to conversion from dates so it perfectly fits to date and time examples

thanks, but credit for noticing that that goes to @alamb for mentioning it in #7013 (comments)

[alamb]

thanks @logan-keede for removing also to_char.rs I doubled checked it and it refers to conversion from dates so it perfectly fits to date and time examples

thanks, but credit for noticing that that goes to @alamb for mentioning it in #7013 (comments)

lol all I do now it seems is to write tickets