Document permissible group ratings (#9236)

diff --git a/doc/lua_api.txt b/doc/lua_api.txt
index 7663b5c9e8f66c5f28eefaec3a44bf40e1d8e970..35be95d513e8c28465ca134c49490f7cff07c417 100644 (file)
--- a/doc/lua_api.txt
+++ b/doc/lua_api.txt
@@ -1481,7 +1481,8 @@ Usage
 -----
 
 Groups are stored in a table, having the group names with keys and the
-group ratings as values. For example:
+group ratings as values. Group ratings are integer values within the
+range [-32767, 32767]. For example:
 
     -- Default dirt
     groups = {crumbly=3, soil=1}