[lldb][NFC] Inclusive Language: Replace master with main

[NFC] This patch fixes a URL within a git repo whose master branch was renamed
to main.

lldb/source/Plugins/ABI/AArch64/ABIMacOSX_arm64.cpp

@@ -402,7 +402,7 @@ bool ABIMacOSX_arm64::CreateDefaultUnwindPlan(UnwindPlan &unwind_plan) {
 // volatile (and specifically only the lower 8 bytes of these regs), the rest
 // of the fp/SIMD registers are volatile.
 //
-// v. https://github.com/ARM-software/abi-aa/blob/master/aapcs64/
+// v. https://github.com/ARM-software/abi-aa/blob/main/aapcs64/
 
 // We treat x29 as callee preserved also, else the unwinder won't try to
 // retrieve fp saves.