message: docs(forms): add usage notes
  Add usage notes for removeValidators and hasValidators to better understand how to use these functions
  PR Close
diff: @@ -676,6 +676,24 @@ export abstract class AbstractControl<TValue = any, TRawValue extends TValue = T
  * validator function as the one that was originally set. If a provided validator is not found,
  * it is ignored.
  *
  + * @usageNotes
  + *
  + * ### Reference to a ValidatorFn
  + *
  + * ```
  + * // Reference to the RequiredValidator
  + * const ctrl = new FormControl<string | null>('', Validators.required);
  + * ctrl.removeValidators(Validators.required);
  + *
  + * // Reference to anonymous function inside MinValidator
  + * const minValidator = Validators.min(3);
  + * const ctrl = new FormControl<string | null>('', minValidator);
  + * expect(ctrl.hasValidator(minValidator)).toEqual(true)
  + * expect(ctrl.hasValidator(Validators.min(3)).toEqual(false)
  + *
  + * ctrl.removeValidators(minValidator);
  + * ```
  + *
  * When you add or remove a validator at run time, you must call
  * `updateValueAndValidity()` for the new validation to take effect.
  *
  @@ -704,6 +722,22 @@ export abstract class AbstractControl<TValue = any, TRawValue extends TValue = T
  * Check whether a synchronous validator function is present on this control. The provided
  * validator must be a reference to the exact same function that was provided.
  *
  + * @usageNotes
  + *
  + * ### Reference to a ValidatorFn
  + *
  + * ```
  + * // Reference to the RequiredValidator
  + * const ctrl = new FormControl<number | null>(0, Validators.required);
  + * expect(ctrl.hasValidator(Validators.required)).toEqual(true)
  + *
  + * // Reference to anonymous function inside MinValidator
  + * const minValidator = Validators.min(3);
  + * const ctrl = new FormControl<number | null>(0, minValidator);
  + * expect(ctrl.hasValidator(minValidator)).toEqual(true)
  + * expect(ctrl.hasValidator(Validators.min(3)).toEqual(false)
  + * ```
  + *
  * @param validator The validator to check for presence. Compared by function reference.
  * @returns Whether the provided validator was found on this control.
  */
  