markdown: Use unicode ellipses for collapsing spoilers.

We had initially implemented this feature using `(...)` but `(…)` is the
better variation.

zerver/lib/push_notifications.py

@@ -534,8 +534,8 @@ def get_mobile_push_content(rendered_content: str) -> str:
         header = elem.find_class('spoiler-header')[0]
         text = process(header).strip()
         if len(text) == 0:
-            return "(...)\n"
+            return "(…)\n"
-        return f"{text} (...)\n"
+        return f"{text} (…)\n"
 
     def process(elem: lxml.html.HtmlElement) -> str:
         plain_text = ''

zerver/tests/fixtures/markdown_test_cases.json

@@ -848,39 +848,39 @@
       "name": "spoilers_fenced_spoiler",
       "input": "```spoiler header\ncontent\n```\noutside spoiler\n",
       "expected_output": "<div class=\"spoiler-block\"><div class=\"spoiler-header\">\n\n<p>header</p>\n</div><div class=\"spoiler-content\" aria-hidden=\"true\">\n\n<p>content</p>\n</div></div>\n\n<p>outside spoiler</p>",
-      "text_content": "header (...)\noutside spoiler"
+      "text_content": "header (…)\noutside spoiler"
     },
     {
       "name": "spoilers_empty_header",
       "input": "```spoiler\ncontent\n```\noutside spoiler\n",
       "expected_output": "<div class=\"spoiler-block\"><div class=\"spoiler-header\">\n\n</div><div class=\"spoiler-content\" aria-hidden=\"true\">\n\n<p>content</p>\n</div></div>\n\n<p>outside spoiler</p>",
-      "text_content": "(...)\noutside spoiler"
+      "text_content": "(…)\noutside spoiler"
     },
     {
       "name": "spoilers_script_tags",
       "input": "```spoiler <script>alert(1)</script>\n<script>alert(1)</script>\n```",
       "expected_output": "<div class=\"spoiler-block\"><div class=\"spoiler-header\">\n\n<p>&lt;script&gt;alert(1)&lt;/script&gt;</p>\n</div><div class=\"spoiler-content\" aria-hidden=\"true\">\n\n<p>&lt;script&gt;alert(1)&lt;/script&gt;</p>\n</div></div>",
       "marked_expected_output": "<div class=\"spoiler-block\"><div class=\"spoiler-header\">\n\n<p>&lt;script&gt;alert(1)&lt;/script&gt;\n\n</p>\n</div><div class=\"spoiler-content\" aria-hidden=\"true\">\n\n<p>&lt;script&gt;alert(1)&lt;/script&gt;\n\n</p>\n</div></div>",
-      "text_content": "<script>alert(1)</script> (...)\n"
+      "text_content": "<script>alert(1)</script> (…)\n"
     },
     {
       "name": "spoilers_block_quote",
       "input": "~~~quote\n```spoiler header\ncontent\n```\noutside spoiler\n~~~\noutside quote",
       "expected_output": "<blockquote>\n<div class=\"spoiler-block\"><div class=\"spoiler-header\">\n\n<p>header</p>\n</div><div class=\"spoiler-content\" aria-hidden=\"true\">\n\n<p>content</p>\n</div></div>\n\n<p>outside spoiler</p>\n</blockquote>\n<p>outside quote</p>",
-      "text_content": "> header (...)\n> outside spoiler\n\noutside quote"
+      "text_content": "> header (…)\n> outside spoiler\n\noutside quote"
     },
     {
       "name": "spoilers_with_header_markdown",
       "input": "```spoiler [Header](https://example.com) :smile:\ncontent\n```",
       "expected_output": "<div class=\"spoiler-block\"><div class=\"spoiler-header\">\n\n<p><a href=\"https://example.com\">Header</a> <span aria-label=\"smile\" class=\"emoji emoji-263a\" role=\"img\" title=\"smile\">:smile:</span></p>\n</div><div class=\"spoiler-content\" aria-hidden=\"true\">\n\n<p>content</p>\n</div></div>",
-      "text_content": "Header ☺ (...)\n"
+      "text_content": "Header ☺ (…)\n"
     },
     {
       "name": "spoiler_with_inline_image",
       "input": "```spoiler header\nContent http://example.com/image.png\n```",
       "expected_output": "<div class=\"spoiler-block\"><div class=\"spoiler-header\">\n\n<p>header</p>\n</div><div class=\"spoiler-content\" aria-hidden=\"true\">\n\n<p>Content <a href=\"http://example.com/image.png\">http://example.com/image.png</a></p>\n<div class=\"message_inline_image\"><a href=\"http://example.com/image.png\"><img data-src-fullsize=\"/thumbnail?url=http%3A%2F%2Fexample.com%2Fimage.png&amp;size=full\" src=\"/thumbnail?url=http%3A%2F%2Fexample.com%2Fimage.png&amp;size=thumbnail\"></a></div></div></div>",
       "marked_expected_output": "<div class=\"spoiler-block\"><div class=\"spoiler-header\">\n\n<p>header</p>\n</div><div class=\"spoiler-content\" aria-hidden=\"true\">\n\n<p>Content <a href=\"http://example.com/image.png\">http://example.com/image.png</a></p>\n</div></div>",
-      "text_content": "header (...)\n"
+      "text_content": "header (…)\n"
     }
   ],
   "linkify_tests": [