docs: Fix duplicate object description warnings

why: Sphinx was warning about duplicate object descriptions
what:
- Add :no-index: to module directives in windows.md, pytest-plugin/index.md,
  and quickstart.md to prevent duplicate indexing
- Remove redundant Attributes section from Pane class docstring
  (window property is already documented by autodoc)

Author: tony

docs/api/windows.md

@@ -7,7 +7,7 @@
 - Identified by `@`, e.g. `@313`
 
 ```{module} libtmux
-
+:no-index:
 ```
 
 ```{eval-rst}

docs/pytest-plugin/index.md

@@ -13,7 +13,7 @@ your case, we won't stabilize APIs until we're sure everything is by the book.
 [connect with us]: https://github.com/tmux-python/libtmux/discussions
 
 ```{module} libtmux.pytest_plugin
-
+:no-index:
 ```
 
 ## Usage

docs/quickstart.md

@@ -129,7 +129,7 @@ $ ptpython
 ```
 
 ```{module} libtmux
-
+:no-index:
 ```
 
 First, we can grab a {class}`Server`.

src/libtmux/pane.py

@@ -56,10 +56,6 @@ class Pane(
     ``Pane`` instances can send commands directly to a pane, or traverse
     between linked tmux objects.
 
-    Attributes
-    ----------
-    window : :class:`Window`
-
     Examples
     --------
     >>> pane