sagemathgh-38464: remove stray r

<!-- ^ Please provide a concise and informative title. -->
<!-- ^ Don't put issue numbers in the title, do this in the PR
description below. -->
<!-- ^ For example, instead of "Fixes sagemath#12345" use "Introduce new method
to calculate 1 + 2". -->
<!-- v Describe your changes below in detail. -->
<!-- v Why is this change required? What problem does it solve? -->
<!-- v If this PR resolves an open issue, please link to it here. For
example, "Fixes sagemath#12345". -->

### 📝 Checklist

<!-- Put an `x` in all the boxes that apply. -->

- [x] The title is concise and informative.
- [x] The description explains in detail what this PR is about.
- [ ] I have linked a relevant issue or discussion.
- [ ] I have created tests covering the changes.
- [ ] I have updated the documentation and checked the documentation
preview.

### ⌛ Dependencies

<!-- List all open PRs that this PR logically depends on. For example,
-->
<!-- - sagemath#12345: short description why this is a dependency -->
<!-- - sagemath#34567: ... -->

URL: sagemath#38464
Reported by: Martin Rubey
Reviewer(s): Frédéric Chapoton

build/pkgs/configure/checksums.ini

@@ -1,3 +1,3 @@
 tarball=configure-VERSION.tar.gz
-sha1=d21dcef9ea75fb52a89af8592796f8a2d97d3f2f
-sha256=ce97f7eecff470cc7dc4c6dce7f0e5e7e85382c2411b23bc6eb9c6934b002ada
+sha1=1aff65e2c5c918efab875b59af6f7a306a1cf54f
+sha256=7c3f03cceffa7a2f96e397d30e374c9dc13d8d17681db96189ae06291f5039c1

build/pkgs/configure/package-version.txt

@@ -1 +1 @@
-f473d0954b37ab99d3530145c0f4536e4f0d88c9
+cb1c224fdaf9dd6865ef401dbb13234734308427

src/sage/categories/examples/algebras_with_basis.py

@@ -52,7 +52,7 @@ def one_basis(self):
         Return the empty word, which index the one of this algebra,
         as per :meth:`AlgebrasWithBasis.ParentMethods.one_basis`.
 
-        EXAMPLES::r
+        EXAMPLES::
 
             sage: A = AlgebrasWithBasis(QQ).example()                                   # needs sage.modules
             sage: A.one_basis()                                                         # needs sage.modules