Remove hanging lines from docstrings. (#2349)

* Remove hanging lines from docstrings.

Deleted hanging blank lines at the end of docstrings.

Regex pattern:
 - find `\n\n( *)"""`
 - replace with `\n$1"""`

tests/snapshot_tests/snapshot_apps/scrollbar_thumb_height.py

@@ -29,7 +29,6 @@ class ScrollViewTester(App[None]):
         background: $primary-darken-2;
         border: round red;
     }
-
     """
 
     def compose(self) -> ComposeResult:

tests/test_animation.py

@@ -9,7 +9,6 @@ class AnimApp(App):
     #foo {
         height: 1;
     }
-
     """
 
     def compose(self) -> ComposeResult:

tests/utilities/render.py

@@ -12,7 +12,6 @@ re_link_ids = re.compile(r"id=[\d\.\-]*?;.*?\x1b")
 def replace_link_ids(render: str) -> str:
     """Link IDs have a random ID and system path which is a problem for
     reproducible tests.
-
     """
     return re_link_ids.sub("id=0;foo\x1b", render)