Use Monokai by default when code_editor is used

Author: darrenburns

src/textual/widgets/_text_area.py

@@ -431,7 +431,7 @@ def code_editor(
         text: str = "",
         *,
         language: str | None = None,
-        theme: str | None = None,
+        theme: str | None = "monokai",
         soft_wrap: bool = False,
         tab_behaviour: Literal["focus", "indent"] = "indent",
         show_line_numbers: bool = True,

tests/snapshot_tests/snapshot_apps/text_area_wrapping.py

@@ -23,7 +23,7 @@
 
 class TextAreaWrapping(App):
     def compose(self) -> ComposeResult:
-        yield TextArea.code_editor(TEXT, language="markdown", soft_wrap=True)
+        yield TextArea.code_editor(TEXT, language="markdown", theme="monokai", soft_wrap=True)
 
 
 app = TextAreaWrapping()

tests/snapshot_tests/test_snapshots.py

@@ -879,8 +879,7 @@ def setup_theme(pilot):
 @pytest.mark.syntax
 def test_text_area_wrapping_and_folding(snap_compare):
     assert snap_compare(
-        SNAPSHOT_APPS_DIR / "text_area_wrapping.py",
-        terminal_size=(20, 26)
+        SNAPSHOT_APPS_DIR / "text_area_wrapping.py", terminal_size=(20, 26)
     )