[releasenote] unduplicate hapod link name

docs/source/release_notes/2021.1.rst

@@ -95,8 +95,8 @@ training routines have been separated from the reductors.
 
 Improvements to the HAPOD algorithm
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-pyMOR's implementation of the
-`HAPOD algorithm <https://epubs.siam.org/doi/abs/10.1137/16M1085413>`_
+pyMOR's implementation of 
+`the HAPOD algorithm <https://epubs.siam.org/doi/abs/10.1137/16M1085413>`_
 has seen several significant improvements in
 `[#1322] <https://github.com/pymor/pymor/pull/1322>`_: