MDL-72871 cleanup: Remove incorrect whitespace from codebase

Differences can be checked with git diff --ignore-all-space and
that will show that the only non-whitespace change is in a test
in the git lib/tests/html2text_test.php file. In that case the
whitespace has been replaced by a quoted string (of whitespaces)
keeping the test 100% equivalent and workarrounding the whitespace.

lib/tests/html2text_test.php

@@ -78,9 +78,9 @@ class core_html2text_testcase extends basic_testcase {
      */
     public function test_build_link_list() {
 
-        // Note the trailing whitespace left intentionally in the text.
+        // Note the trailing whitespace left intentionally in the text after first link.
         $text = 'Total of <a title="List of integrated issues"
-            href="http://tr.mdl.org/sh.jspa?r=1&j=p+%3D+%22I+d%22+%3D">     
+            href="http://tr.mdl.org/sh.jspa?r=1&j=p+%3D+%22I+d%22+%3D">     ' . '
             <strong>27 issues</strong></a> and <a href="http://another.url/?f=a&amp;b=2">some</a> other
 have been fixed <strong><a href="http://third.url/view.php">last week</a></strong>';