[lldb] Hyphenate Objective-C exception breakpoint labels ✍️

Objective-C is officially hyphenated:
https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/ObjectiveC/Introduction/introObjectiveC.html#//apple_ref/doc/uid/TP30001163

Reviewed By: mwyman, clayborg

Differential Revision: https://reviews.llvm.org/D113616