small version compatibility fixes

Updated for 1.21.2+
see last version's changelog

• run function as_health:default_armor_stand_health {value:<hp as an integer>} to change the default health of existing and future armor stands.
  • is a whole number (vanilla is 20)
• /trigger armor_stand_arms_on_closest gives the closest armor stand within 5 blocks arms.

Updated to 1.21

1.20.5