Fix CI COPY-FROM failures for _assert and inverse docs

Replace COPY-FROM directives with inline code examples since the
CI nightly Paddle wheel does not include these new APIs yet.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Manfredss

docs/api/paddle/_assert_cn.rst

@@ -17,4 +17,12 @@ _assert
 代码示例
 ::::::::::::
 
-COPY-FROM: paddle._assert
+.. code-block:: pycon
+
+    >>> import paddle
+    >>> # Non-tensor condition
+    >>> paddle._assert(1 == 1, "This should pass")
+
+    >>> # Tensor condition
+    >>> x = paddle.to_tensor([True])
+    >>> paddle._assert(x, "Tensor assertion")

docs/api/paddle/inverse_cn.rst

@@ -23,4 +23,13 @@ Tensor，``x`` 的逆矩阵，维度和数据类型与 ``x`` 相同。
 代码示例
 ::::::::::::
 
-COPY-FROM: paddle.inverse
+.. code-block:: pycon
+
+    >>> import paddle
+
+    >>> mat = paddle.to_tensor([[2, 0], [0, 2]], dtype='float32')
+    >>> inv = paddle.inverse(mat)
+    >>> print(inv)
+    Tensor(shape=[2, 2], dtype=float32, place=Place(cpu), stop_gradient=True,
+    [[0.50000000, 0.        ],
+     [0.        , 0.50000000]])