Add unprefixed versions of align/justify properties to align/justify classes

[Dan503]

@gcoda
did i miss a note on justify\align\content ?

.content-stretch { align-content: stretch } is possible and useful on grid.
I am also missing ~ self-justify-center: { justify-self: center } and i am not sure hot this should be called, but already using it...
#1274 (comment)

These should technically already be supported since CSS Grid and Flexbox both share the justify and align properties. However based on the Tailwind documentation, it looks like it only supports the old Flexbox only syntax.

.justify-start {
    justify-content: flex-start;
}

https://tailwindcss.com/docs/justify-content/#app

These justify and alignment properties should be updated to also support CSS Grid.

.justify-start {
   /* "flex-start" in-case the browser doesn't understand "start" on it's own */
    justify-content: flex-start;
    justify-content: start;
}

Affected properties:

• align-content
• justify-content
• place-content
• align-items
• justify-items
• place-items
• align-self
• justify-self
• place-self

[DNature]

Hello everyone. I was about to open an issue before i noticed similar issue:
Affected properties:

-place-content
-justify-items
-place-items
-justify-self
-place-self

I really love tailwindcss and i wanna contribute to it because that's the most i could do at the moment.
Is it fine if i go ahead and implement these features since it's not been implemented yet?