docs(forms): migrate deprecated @howToUse tags (#23186)

In this case they have been converted to `@description` tags.

PR Close #23186

packages/forms/src/directives/reactive_directives/form_control_directive.ts

@@ -36,7 +36,7 @@ export const formControlBinding: any = {
  * any values written to the DOM element through user input will be reflected in the
  * {@link FormControl} instance (view -> model).
  *
- * @howToUse
+ * @description
  *
  * Use this directive if you'd like to create and manage a {@link FormControl} instance directly.
  * Simply create a {@link FormControl}, save it to your component class, and pass it into the

packages/forms/src/directives/reactive_directives/form_control_name.ts

@@ -36,7 +36,7 @@ export const controlNameBinding: any = {
  * any values written to the DOM element through user input will be reflected in the
  * {@link FormControl} instance (view -> model).
  *
- * @howToUse
+ * @description
  *
  * This directive is designed to be used with a parent {@link FormGroupDirective} (selector:
  * `[formGroup]`).

packages/forms/src/directives/reactive_directives/form_group_directive.ts

@@ -25,7 +25,7 @@ export const formDirectiveProvider: any = {
 /**
  * @whatItDoes Binds an existing {@link FormGroup} to a DOM element.
  *
- * @howToUse
+ * @description
  *
  * This directive accepts an existing {@link FormGroup} instance. It will then use this
  * {@link FormGroup} instance to match any child {@link FormControl}, {@link FormGroup},

packages/forms/src/directives/reactive_directives/form_group_name.ts

@@ -26,7 +26,7 @@ export const formGroupNameProvider: any = {
 /**
  * @whatItDoes Syncs a nested {@link FormGroup} to a DOM element.
  *
- * @howToUse
+ * @description
  *
  * This directive can only be used with a parent {@link FormGroupDirective} (selector:
  * `[formGroup]`).
@@ -97,7 +97,7 @@ export const formArrayNameProvider: any = {
 /**
  * @whatItDoes Syncs a nested {@link FormArray} to a DOM element.
  *
- * @howToUse
+ * @description
  *
  * This directive is designed to be used with a parent {@link FormGroupDirective} (selector:
  * `[formGroup]`).