doc(validation): document the defaultValidationTrigger config option

See aurelia-validation release 1.6.0

Author: RomkeVdMeulen

current/en-us/7. plugins/3. validation.md

@@ -285,6 +285,29 @@ export class RegistrationForm {
 }
 ```
 
+#### Changing the default Validate Trigger
+
+You can configure the default validation trigger that every controller uses without having to change each controller yourself. You can access the validation configuration when you register the validation plugin during bootstrapping.
+
+```JavaScript Configuring the default validate trigger
+import {validateTrigger} from "aurelia-validation";
+
+export function configure(aurelia) {
+  aurelia.use.plugin("aurelia-validation", config => {
+    config.defaultValidationTrigger(validateTrigger.manual);
+  });
+}
+```
+```TypeScript Configuring the default validate trigger
+import {GlobalValidationConfiguration, validateTrigger} from "aurelia-validation";
+
+export function configure(aurelia) {
+  aurelia.use.plugin("aurelia-validation", (config: GlobalValidationConfiguration) => {
+    config.defaultValidationTrigger(validateTrigger.manual);
+  });
+}
+```
+
 ### validate & reset
 
 You can force the validation controller to run validation by invoking the `validate()` method. Validate will run the validation, render the results and return a `Promise` that resolves with a `ControllerValidateResult` instance. *The promise will only reject when there is an unexpected application error. Be sure to catch these rejections like you would any other unexpected application error.*