Swap out the primary Markdown bullet for one that works everywhere (#1997)

* Swap out the primary Markdown bullet for one that works everywhere

The primary bullet wasn't displaying well on Windows in the Windows
terminal.

* Refresh the snapshot tests

Imagine that, changing how something looks needs that the snapshot tests get
updated. *facepalm*

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Updated styling to make it clear DataTable grows horizontally https://github.com/Textualize/textual/pull/1946
 - Changed the `Checkbox` character due to issues with Windows Terminal and Windows 10 https://github.com/Textualize/textual/issues/1934
 - Changed the `RadioButton` character due to issues with Windows Terminal and Windows 10 and 11 https://github.com/Textualize/textual/issues/1934
+- Changed the `Markdown` initial bullet character due to issues with Windows Terminal and Windows 10 and 11 https://github.com/Textualize/textual/issues/1982
 
 ### Added
 

src/textual/widgets/_markdown.py

@@ -393,7 +393,7 @@ class MarkdownBullet(Widget):
     }
     """
 
-    symbol = reactive("●​")
+    symbol = reactive("\u25CF")
     """The symbol for the bullet."""
 
     def render(self) -> Text:
@@ -500,7 +500,7 @@ class Markdown(Widget):
     """
     COMPONENT_CLASSES = {"em", "strong", "s", "code_inline"}
 
-    BULLETS = ["⏺ ", "▪ ", "‣ ", "• ", "⭑ "]
+    BULLETS = ["\u25CF ", "▪ ", "‣ ", "• ", "⭑ "]
 
     def __init__(
         self,