message: Updated README with env var values
diff: @@ -23,3 +23,15 @@ Tweaks stuff. See below.
  * `NWNX_TWEAKS_FIX_GREATER_SANCTUARY_BUG`: true or false
  * `NWNX_TWEAKS_FIX_SCROLL_LEARNING_BUG`: true or false
  * `NWNX_TWEAKS_ITEM_CHARGES_COST_MODE`: Between 1 and 3
  +
  +## Environment variable values
  +
  +### NWNX_TWEAKS_ITEM_CHARGES_COST_MODE
  +Values between 1 and 3 are valid. Any of those values will adjust the item cost to the old values used in 1.69 for items with 50 charges or less.
  +
  +| Value | Description |
  +|---:|----|
  +| 1 | Cost will be capped at 50 charges. Any charges over 50 won't affect the item cost. |
  +| 2 | Up to 50 charges the cost will be the same as it was in 1.69. Any charges over 50 will add less value, capping at twice the cost at 250 charges. |
  +| 3 | Cost will be calculated linearly based on the number of charges the same it was in 1.69, making items with 250 charges 5 times as expensive as 50 charges ones. |
  +
  