fix: grammar in godoc for NotErrorIs(f) functions (#1607)

Grammar fixes in doc: _asserts that at none_ -> _asserts that none_

$ grep 'that at none' */*.go
assert/assertion_format.go:// NotErrorIsf asserts that at none of the errors in err's chain matches target.
assert/assertion_forward.go:// NotErrorIs asserts that at none of the errors in err's chain matches target.
assert/assertion_forward.go:// NotErrorIsf asserts that at none of the errors in err's chain matches target.
assert/assertions.go:// NotErrorIs asserts that at none of the errors in err's chain matches target.
require/require.go:// NotErrorIs asserts that at none of the errors in err's chain matches target.
require/require.go:// NotErrorIsf asserts that at none of the errors in err's chain matches target.
require/require_forward.go:// NotErrorIs asserts that at none of the errors in err's chain matches target.
require/require_forward.go:// NotErrorIsf asserts that at none of the errors in err's chain matches target.

Author: miparnisari

assert/assertion_format.go

@@ -2094,7 +2094,7 @@ func ErrorIs(t TestingT, err, target error, msgAndArgs ...interface{}) bool {
 	), msgAndArgs...)
 }
 
-// NotErrorIs asserts that at none of the errors in err's chain matches target.
+// NotErrorIs asserts that none of the errors in err's chain matches target.
 // This is a wrapper for errors.Is.
 func NotErrorIs(t TestingT, err, target error, msgAndArgs ...interface{}) bool {
 	if h, ok := t.(tHelper); ok {