[lld][InstrProf][NFC] Fix typo in help message (#123390)

Author: ellishg

lld/MachO/Options.td

@@ -133,7 +133,7 @@ def print_symbol_order_eq: Joined<["--"], "print-symbol-order=">,
 def irpgo_profile: Separate<["--"], "irpgo-profile">, Group<grp_lld>;
 def irpgo_profile_eq: Joined<["--"], "irpgo-profile=">,
     Alias<!cast<Separate>(irpgo_profile)>, MetaVarName<"<profile>">,
-    HelpText<"Read the IRPGO <profile> for use with -bp-startup-sort and other profile-guided optimizations">,
+    HelpText<"Read the IRPGO <profile> for use with --bp-startup-sort and other profile-guided optimizations">,
     Group<grp_lld>;
 def bp_startup_sort: Joined<["--"], "bp-startup-sort=">,
     MetaVarName<"[none,function]">,