Resolve all paths in the include directive (#11650)

Because pytest's base tmp_path is also in /tmp, ``source`` here is relative path,
and thus is not properly converted to doc name.

So the test fails because `sources_reported` dict has a key like
``../../../pytest/pytest-0/directive-include/baz/baz``,
and ``assert "baz/baz" in sources_reported`` fails.

Co-authored-by: Adam Turner <9087854+aa-turner@users.noreply.github.com>

sphinx/directives/other.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import re
+from os.path import abspath
 from typing import TYPE_CHECKING, Any, cast
 
 from docutils import nodes
@@ -386,7 +387,7 @@ class Include(BaseInclude, SphinxDirective):
             text = "\n".join(include_lines[:-2])
 
             # The docname to pass into the source-read event
-            docname = self.env.path2doc(os_path(source))
+            docname = self.env.path2doc(abspath(os_path(source)))
             # Emit the "source-read" event
             arg = [text]
             self.env.app.events.emit("source-read", docname, arg)