[6.x] Fix nullable return types in form docblocks

src/Contracts/Forms/Form.php

@@ -40,7 +40,7 @@ public function submissions();
      * Get a submission.
      *
      * @param  string  $id
-     * @return Submission
+     * @return Submission|null
      */
     public function submission($id);
 

src/Facades/Form.php

@@ -8,7 +8,7 @@
 use Statamic\Forms\Exporters\ExporterRepository;
 
 /**
- * @method static \Statamic\Contracts\Forms\Form find(string $handle)
+ * @method static \Statamic\Contracts\Forms\Form|null find(string $handle)
  * @method static \Statamic\Contracts\Forms\Form findOrFail(string $handle)
  * @method static \Illuminate\Support\Collection all()
  * @method static int count()

src/Facades/FormSubmission.php

@@ -12,7 +12,7 @@
  * @method static Collection all()
  * @method static Collection whereForm(string $handle)
  * @method static Collection whereInForm(array $handles)
- * @method static SubmissionContract find($id)
+ * @method static SubmissionContract|null find($id)
  * @method static void save(SubmissionContract $submission)
  * @method static void delete(SubmissionContract $submission)
  * @method static SubmissionQueryBuilder query()

src/Forms/Form.php

@@ -349,7 +349,7 @@ public function querySubmissions(): SubmissionQueryBuilder
      * Get a submission.
      *
      * @param  string  $id
-     * @return Submission
+     * @return Submission|null
      */
     public function submission($id)
     {

src/Forms/FormRepository.php

@@ -22,7 +22,7 @@ class FormRepository implements Contract
      * Find a form.
      *
      * @param  string  $handle
-     * @return FormContract
+     * @return FormContract|null
      */
     public function find($handle)
     {