Document ale#Has

doc/ale.txt

@@ -2539,6 +2539,14 @@ ale#Env(variable_name, value)                                       *ale#Env()*
     'set VAR="some value" && command' # On Windows
 
 
+ale#Has(feature)                                                    *ale#Has()*
+
+  Return `1` if ALE supports a given feature, like |has()| for Vim features.
+
+  ALE versions can be checked with version strings in the format
+  `ale#Has('ale-x.y.z')`, such as `ale#Has('ale-2.4.0')`.
+
+
 ale#Pad(string)                                                     *ale#Pad()*
 
   Given a string or any |empty()| value, return either the string prefixed