tests README: re-flow a previously changed paragraph

A previous change to the "GIT_TEST_GETTEXT_POISON" variable left this
paragraph needing to be re-flowed. Let's do that in this separate
change to make it easy to see that there's no change here when viewed
with "--word-diff".

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/README

@@ -344,10 +344,10 @@ refactor to deal with it. The "SYMLINKS" prerequisite is currently
 excluded as so much relies on it, but this might change in the future.
 
 GIT_TEST_GETTEXT_POISON=<boolean> turns all strings marked for
-translation into gibberish if true. Used for
-spotting those tests that need to be marked with a C_LOCALE_OUTPUT
-prerequisite when adding more strings for translation. See "Testing
-marked strings" in po/README for details.
+translation into gibberish if true. Used for spotting those tests that
+need to be marked with a C_LOCALE_OUTPUT prerequisite when adding more
+strings for translation. See "Testing marked strings" in po/README for
+details.
 
 GIT_TEST_SPLIT_INDEX=<boolean> forces split-index mode on the whole
 test suite. Accept any boolean values that are accepted by git-config.