CoreExtension : Make error message more readable

[tcoch]

It's a silly little patch, but really improves the readability of the error message IMO ...

[GromNaN]

Well spotted!
You have to update the expected message in tests:

Twig/tests/TemplateTest.php

Lines 89 to 90 in d58c8be

	['{{ array_access.a }}', 'Neither the property "a" nor one of the methods "a()", "geta()"/"isa()"/"hasa()" or "__call()" exist and have public access in class "Twig\Tests\TemplateArrayAccessObject" in "%s" at line 1.'],
	['{% from _self import foo %}{% macro foo(obj) %}{{ obj.missing_method() }}{% endmacro %}{{ foo(array_access) }}', 'Neither the property "missing_method" nor one of the methods "missing_method()", "getmissing_method()"/"ismissing_method()"/"hasmissing_method()" or "__call()" exist and have public access in class "Twig\Tests\TemplateArrayAccessObject" in "%s" at line 1.'],

[fabpot]

Thank you @tcoch.