Rescale town cargo adj setting by 10x, for finer adjustment.

Use DECIMAL1 instead of an integer.

src/lang/english.txt

@@ -1666,6 +1666,7 @@ STR_CONFIG_SETTING_TOWN_FOUNDING_FORBIDDEN                      :Forbidden
 STR_CONFIG_SETTING_TOWN_FOUNDING_ALLOWED                        :Allowed
 STR_CONFIG_SETTING_TOWN_FOUNDING_ALLOWED_CUSTOM_LAYOUT          :Allowed, custom town layout
 STR_CONFIG_SETTING_TOWN_CARGO_FACTOR                            :Town cargo generation factor (less < 0 < more): {STRING2}
+STR_CONFIG_SETTING_TOWN_CARGO_FACTOR_HELPTEXT                   :Passenger, mail, and other town cargo production is scaled by approximately 2^factor (exponential)
 
 STR_CONFIG_SETTING_EXTRA_TREE_PLACEMENT                         :In game placement of trees: {STRING2}
 STR_CONFIG_SETTING_EXTRA_TREE_PLACEMENT_HELPTEXT                :Control random appearance of trees during the game. This might affect industries which rely on tree growth, for example lumber mills