bug #5501 Fix typo in url for PHPUnit test coverage report (TrueGit)

This PR was merged into the 2.7 branch.

Discussion
----------

Fix typo in url for PHPUnit test coverage report

| Q                 | A
| -------------    | ---
| Doc fix?        | yes
| New docs?   | no
| Applies to     | 2.7
| Fixed tickets | NA?

In symfony-docs/create_framework/unit-testing.rst, on topic of using
PHPUnit to create a test coverage report, it appears the path to the
report should be "example.com/cov/src/Simplex/Framework.php.html"
instead of "example.com/cov/src_Simplex_Framework.php.html".

Commits
-------

e5ea3f0 Fix typo in url for PHPUnit test coverage report

create_framework/unit-testing.rst

@@ -178,7 +178,7 @@ coverage feature (you need to enable `XDebug`_ first):
 
     $ phpunit --coverage-html=cov/
 
-Open ``example.com/cov/src_Simplex_Framework.php.html`` in a browser and check
+Open ``example.com/cov/src/Simplex/Framework.php.html`` in a browser and check
 that all the lines for the Framework class are green (it means that they have
 been visited when the tests were executed).