Update comment endpoint

----------------------------------

- Adjust documentation to retrieve all comments (Issue ID is required)
- Allow to create new comments
- Update comment default fields

docs/issues/comments.md

@@ -4,7 +4,7 @@ $youtrack->issues()
          ->comments()
 ```
 
-##### `all()`
+##### `all($issueId)`
 Returns all issue comments.
 
 ##### `one($issueId, $commentId)`
@@ -18,8 +18,12 @@ Returns a specific issue based on the issue and comment ID.
     'textPreview',
     'created',
     'updated',
-    'author',
-    'issue',
+    'author' => [
+        'name'
+    ],
+    'issue' => [
+        'idReadable'
+    ],
     'attachments',
     'visibility',
     'deleted'

src/Api/Issue/Comment.php

@@ -17,8 +17,12 @@ protected function defaultFields(): self
             'textPreview',
             'created',
             'updated',
-            'author',
-            'issue',
+            'author' => [
+                'name'
+            ],
+            'issue' => [
+                'idReadable'
+            ],
             'attachments',
             'visibility',
             'deleted'
@@ -42,4 +46,12 @@ public function one(string $issueId, string $commentId): array
     {
         return $this->get("issues/$issueId/comments/$commentId");
     }
+
+    /**
+     * Create issue comment.
+     */
+    public function create(string $issueId, array $parameter): array
+    {
+        return $this->post("issues/$issueId/comments", $parameter);
+    }
 }