Fix docstring markup in sage/tests except sage/tests/book_stein_modform.py

[kwankyu]

Part of #34157:

sage/tests/benchmark.py:68:1: RST203 Definition list ends without a blank line; unexpected unindent.
sage/tests/article_heuberger_krenn_kropf_fsm-in-sage.py:10:1: RST301 Unexpected indentation.
sage/tests/article_heuberger_krenn_kropf_fsm-in-sage.py:13:1: RST201 Block quote ends without a blank line; unexpected unindent.
sage/tests/gosper-sum.py:2:1: RST399 Document or section may not begin with a transition.

Component: documentation

Author: Frédéric Chapoton

Branch/Commit: 24e01a2

Reviewer: Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/34166

[kwankyu]

Description changed:

--- 
+++ 
@@ -1,3 +1,4 @@
+Part of #34157:
 
 ```
 sage/tests/benchmark.py:68:1: RST203 Definition list ends without a blank line; unexpected unindent.

[fchapoton]

comment:2

done and checked (green except the Stein book)

---

New commits:

24e01a2

rst fixes in tests

[fchapoton]

Branch: u/chapoton/34166

[fchapoton]

Commit: 24e01a2

[fchapoton]

Author: Frédéric Chapoton

[mkoeppe]

Reviewer: Matthias Koeppe

[vbraun]

Changed branch from u/chapoton/34166 to 24e01a2