fix: addapt doc to match last evolution

Author: pgrange

README.adoc

@@ -206,6 +206,7 @@ Running tests in tests/test_core.sh
 	Running test_fake_transmits_params_to_fake_code ... SUCCESS
 	Running test_fake_transmits_params_to_fake_code_as_array ... SUCCESS
 	Running test_should_pretty_format_even_when_LANG_is_unset ... SUCCESS
+	Running test_should_pretty_format_even_with_pipefail_set ... SUCCESS
 Overall result: SUCCESS
 ```
 
@@ -315,7 +316,8 @@ ok - test_fake_exports_faked_in_subshells
 ok - test_fake_transmits_params_to_fake_code
 ok - test_fake_transmits_params_to_fake_code_as_array
 ok - test_should_pretty_format_even_when_LANG_is_unset
-1..30
+ok - test_should_pretty_format_even_with_pipefail_set
+1..31
 ```
 
 == How to write tests