DOC fix minor sphinx issues (scikit-learn#12653)

Author: amueller

doc/testimonials/testimonials.rst

@@ -76,7 +76,7 @@ Erik Bernhardsson, Engineering Manager Music Discovery & Machine Learning, Spoti
  </span>
 
 `Inria <https://www.inria.fr/>`_
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+--------------------------------
 
 .. raw:: html
 
@@ -255,7 +255,7 @@ Alexandre Gramfort, Assistant Professor
 
 
 `Booking.com <https://www.booking.com>`_
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+-----------------------------------------
 .. raw:: html
 
  <div class="logo">
@@ -728,7 +728,7 @@ Guillaume Lebourgeois & Samuel Charron - Data Scientists at Data Publica
 
 
 `Machinalis <https://www.machinalis.com/>`_
------------------------------------------
+-------------------------------------------
 
 .. raw:: html
 
@@ -937,7 +937,7 @@ Vlasios Vasileiou, Head of Data Science, Zopa
  </span>
 
 `MARS <https://www.mars.com/global>`_
-------------------------------------
+--------------------------------------
 
 .. raw:: html
 

doc/whats_new/v0.20.rst

@@ -96,7 +96,7 @@ Changelog
  :issue:`12388` by :user:`Connor Tann <Connossor>`.
 
 :mod:`sklearn.feature_extraction`
-...........................
+..................................
 
 - |Fix| Fixed a regression in v0.20.0 where
  :func:`feature_extraction.text.CountVectorizer` and other text vectorizers
@@ -154,7 +154,7 @@ Changelog
  :issue:`12171` by :user:`Thomas Moreau <tomMoral>`.
 
 :mod:`sklearn.preprocessing`
-........................
+.............................
 
 - |Fix| Fixed bug in :class:`preprocessing.OrdinalEncoder` when passing
  manually specified categories. :issue:`12365` by `Joris Van den Bossche`_.