Avoid docks when scrolling (#2571)

* handle docked layers

* handle scroll better

* snapshot update

* remove commented out code

* superflous

* dock gutter

* snapshit

* snapshit test

* changelog

* mistake

* docstrings

* changelog

* whitespace

* missing punctuation

* ofx docstring

* Apply suggestions from code review

Co-authored-by: Rodrigo Girão Serrão <5621605+rodrigogiraoserrao@users.noreply.github.com>

---------

Co-authored-by: Rodrigo Girão Serrão <5621605+rodrigogiraoserrao@users.noreply.github.com>

tests/snapshot_tests/snapshot_apps/scroll_to.py

@@ -0,0 +1,19 @@
+from textual.app import App, ComposeResult
+from textual.widgets import Checkbox, Footer
+
+
+class ScrollOffByOne(App):
+    """Scroll to item 50."""
+
+    def compose(self) -> ComposeResult:
+        for number in range(1, 100):
+            yield Checkbox(str(number), id=f"number-{number}")
+        yield Footer()
+
+    def on_ready(self) -> None:
+        self.query_one("#number-50").scroll_visible()
+
+
+app = ScrollOffByOne()
+if __name__ == "__main__":
+    app.run()