document incompatible rules (#2710)

Author: pq

lib/src/rules/always_specify_types.dart

@@ -85,7 +85,8 @@ class AlwaysSpecifyTypes extends LintRule implements NodeLintRule {
             group: Group.style);
 
   @override
-  List<String> get incompatibleRules => const ['omit_local_variable_types'];
+  List<String> get incompatibleRules =>
+      const ['avoid_types_on_closure_parameters', 'omit_local_variable_types'];
 
   @override
   void registerNodeProcessors(

lib/src/rules/avoid_types_on_closure_parameters.dart

@@ -37,6 +37,9 @@ class AvoidTypesOnClosureParameters extends LintRule implements NodeLintRule {
             details: _details,
             group: Group.style);
 
+  @override
+  List<String> get incompatibleRules => const ['always_specify_types'];
+
   @override
   void registerNodeProcessors(
       NodeLintRegistry registry, LinterContext context) {