swapping a certain item should adjust a certain form

wording this awkwardly so ppl dont get mad about spoilers. it's about armored mewtwo and it fixes #1132

Author: itsdarsh

engine/pokemon/mon_menu.asm

@@ -375,7 +375,7 @@ PCGiveItem:
 SwapPartyItem:
 	ld a, [wPartyCount]
 	cp 2
-	jr c, .DontSwap
+	jmp c, .DontSwap
 	ld a, [wCurPartyMon]
 	inc a
 	ld [wSwitchMon], a
@@ -407,11 +407,11 @@ SwapPartyItem:
 	; First, swap mail metadata. Don't bother checking if we are holding Mail,
 	; doing the swap either way is harmless and simplifies checks.
 	; Note that wCurPartyMon is 0-indexed while wSwitchMon is 1-indexed.
-	push bc
-	push de
 	ld a, [wCurPartyMon]
-	inc a
 	ld c, a
+	push bc
+	push de
+	inc c
 	ld a, [wSwitchMon]
 	ld e, a
 	farcall SwapPartyMonMail
@@ -422,22 +422,38 @@ SwapPartyItem:
 	; wCurPartyMon contains second selected pkmn
 	; getting pkmn2 item and putting into stack item addr + item id
 	call GetPartyItemLocation
-	ld a, [hl] ; a pkmn2 contains item
+	ld a, [hl] ; a contains pkmn2 item
 	push hl
 	push af
 	; getting pkmn 1 item and putting item id into b
 	ld a, [wSwitchMon]
 	dec a
 	ld [wCurPartyMon], a
 	call GetPartyItemLocation
-	ld a, [hl] ; a pkmn1 contains item
+	ld a, [hl] ; a contains pkmn1 item
 	ld b, a
 	; actual swap
 	pop af
-	ld [hl], a ; pkmn1 get pkm2 item
+	ld [hl], a ; pkmn1 get pkmn2 item
+	xor a ; ld a, MON_SPECIES
+	push hl
+	call GetPartyParamLocationAndValue
+	pop hl
+	ld [wCurPartySpecies], a ; load pkmn1 species
+	push bc
+	call UpdateMewtwoForm
+	pop bc
 	pop hl
 	ld a, b
-	ld [hl], a ; pkmn1 get pkm2 item
+	ld [hl], a ; pkmn2 get pkmn1 item
+	ld a, c
+	ld [wCurPartyMon], a ; restore pkmn2
+	xor a ; ld a, MON_SPECIES
+	push hl
+	call GetPartyParamLocationAndValue
+	pop hl
+	ld [wCurPartySpecies], a ; load pkmn2 species
+	call UpdateMewtwoForm
 	xor a
 	ld [wPartyMenuActionText], a
 	jmp CancelPokemonAction