t/README: fix multi-prerequisite example

With the broken quoting the test wouldn't even parse correctly, but
there's also the '==' instead of POSIX '=' (of the shells I tested,
busybox ash, bash and ksh (93 and OpenBSD) accept '==', dash and zsh do
not), and 'print 2' from Python 2 days.

(I assume the test failing due to 3 != 4 is intentional or immaterial.)

Fixes: 93a5724 ("test-lib: Add support for multiple test prerequisites")
Signed-off-by: Štěpán Němec <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: stepnem

t/README

@@ -887,7 +887,7 @@ see test-lib-functions.sh for the full list and their options.
    rare case where your test depends on more than one:
 
 	test_expect_success PERL,PYTHON 'yo dawg' \
-	    ' test $(perl -E 'print eval "1 +" . qx[python -c "print 2"]') == "4" '
+	    ' test $(perl -E '\''print eval "1 +" . qx[python -c "print(2)"]'\'') = "4" '
 
  - test_expect_failure [<prereq>] <message> <script>