format file with non-ascii characters

[plubanski]

Formatting files with non-ascii characters doesn't work.
It's easier to show than describe whats wrong.
input file:

#import "Example.h"
// ń
@implementation Example
-(void) doSomethingWithString:(NSString*) string{
}
@end

expected result with WebKit style

#import "Example.h"
// ń
@implementation Example
- (void)doSomethingWithString:(NSString*)string
{
}
@end

actual result

#import "Example.h"
// ń
@implementation Example
-( void) oSomethingWithString:(NSString*) tring{

}
@end

when i remove ń letter from comment everything works as expected.
Formatting this file with command line clang-fomat works.