Add support for page and block level ignores (#33)

tests/roots/basic/page_with_ignore_blocks.rst

@@ -0,0 +1,39 @@
+Page With Ignore Blocks
+=======================
+
+This content should appear in llms-full.txt.
+
+.. llms-txt-ignore-start
+
+This content should be ignored and not appear in llms-full.txt.
+
+Section Ignored
+---------------
+
+This section should also be ignored.
+
+.. llms-txt-ignore-end
+
+This content after the ignore block should appear in llms-full.txt.
+
+Another Section
+---------------
+
+This content should definitely appear.
+
+.. llms-txt-ignore-start
+
+Another ignored block with multiple lines.
+
+- Item 1 (ignored)
+- Item 2 (ignored)
+
+.. code-block:: python
+
+   # This code should be ignored
+   def ignored_function():
+       pass
+
+.. llms-txt-ignore-end
+
+Final content that should appear.