Add set_ne aliases to ActiveValue

[WaterWhisperer]

PR Info

• Closes Shorter name for set_if_not_equals #2977

Changes

• add ActiveValue::set_ne as a shorter alias for set_if_not_equals
• add ActiveValue::set_ne_and as a shorter alias for set_if_not_equals_and
• keep the existing methods as compatibility aliases
• update the ActiveValue docs and examples in both sea-orm and sea-orm-sync to prefer the shorter names

[WaterWhisperer]

Note that ActiveModelTrait also has set_if_not_equals, but it's a trait instead of an enum like ActiveValue, maybe it doesn't need a shorter set_ne?

[WaterWhisperer]

Also, since set_if_not_equals is retained as an alias, I haven't updated the original call to set_ne. Looking forward to receiving reviews and thoughts.

[Huliiiiii]

Actually, I prefer set_if_ne. set_ne feels a bit unnatural to me.

[Expurple]

I slightly prefer set_ne over set_if_ne because it's shorter and clear enough to me.

[WaterWhisperer]

Seems that there are different opinions on the short name, perhaps more opinions are needed :)

[Expurple]

@tyt2y3