Change recommended linker: zld to lld for MacOS (#7496)

# Objective

Stop recommending zld on MacOS
Fixes #7299 

## Solution

- Add instructions to install lld for MacOS

.cargo/config_fast_builds

@@ -7,13 +7,21 @@
 linker = "clang"
 rustflags = ["-Clink-arg=-fuse-ld=lld", "-Zshare-generics=y"]
 
-# NOTE: you must manually install https://github.com/michaeleisel/zld on mac. you can easily do this with the "brew" package manager:
-# `brew install michaeleisel/zld/zld`
+# NOTE: you must install [Mach-O LLD Port](https://lld.llvm.org/MachO/index.html) on mac. you can easily do this by installing llvm which includes lld with the "brew" package manager:
+# `brew install llvm`
 [target.x86_64-apple-darwin]
-rustflags = ["-C", "link-arg=-fuse-ld=/usr/local/bin/zld", "-Zshare-generics=y"]
+rustflags = [
+    "-C",
+    "link-arg=-fuse-ld=/usr/local/opt/llvm/bin/ld64.lld",
+    "-Zshare-generics=y",
+]
 
 [target.aarch64-apple-darwin]
-rustflags = ["-C", "link-arg=-fuse-ld=/opt/homebrew/bin/zld", "-Zshare-generics=y"]
+rustflags = [
+    "-C",
+    "link-arg=-fuse-ld=/opt/homebrew/opt/llvm/bin/ld64.lld",
+    "-Zshare-generics=y",
+]
 
 [target.x86_64-pc-windows-msvc]
 linker = "rust-lld.exe"