Revives heavy revolver ammo

[Git-Nivrak]

About the pull request

This PR re-adds the stun to heavy revolver ammo and increases its fire delay (only for heavy impact ammo)

Explain why it's good for the game

Heavy revolver ammo went from something you'd race for at the start of the round to completely useless ammo nobody ever uses.
This PR aims to make it more appealing by returning its stun gimmick without the stunlock, allowing for xenos hit to disengage.

Testing Photographs and Procedure

Screenshots & Videos

Put screenshots and videos here with an empty line between the screenshots and the <details> tags.

Changelog

🆑
balance: Heavy revolver ammo now stuns instead of knocking back but also increases the fire delay by one second.
/:cl:

[HeresKozmos]

I'm not keen on seeing the resurfacing of pocket stuns with virtually no warning which essentially anyone can carry on their person.

[Steelpoint]

I feel this change would only be viable if something is done to address the core underlying issue of the lack of any readability of the stun, or if the after a xeno is stunned they have a cooldown of invulnerability to further stuns to give them a chance to recover, as per our last discussion here: #4706

[Git-Nivrak]

The chance to recover is the extra one second of fire delay which is an alternative solution to #4706

[HeresKozmos]

The chance to recover is the extra one second of fire delay which is an alternative solution to #4706

Yes but then there's the secondary issue of there being something to tell you what's coming, you can easily just press E to pull out the M44 and shoot someone, even if the stun is now on a delay there's still nothing telling you that you're about to get stunned.

[Drulikar]

I am content with the solution done in 4706.