Recommend download via CLI on macOS (#5682)

docs: recommend download via CLI on macOS

otherwise (browser) one has to remove the quarantine xattr.

docs/installation.rst

@@ -110,8 +110,9 @@ are available on the releases_ page for the following platforms:
 
 * **Linux**: glibc >= 2.13 (ok for most supported Linux releases).
   Older glibc releases are untested and may not work.
-* **MacOS**: 10.10 or newer (To avoid signing issues, remove the ``quarantine`` attribute 
-  after downloading: ``$ xattr -dr com.apple.quarantine borg-macosx64.tgz``)
+* **MacOS**: 10.10 or newer (To avoid signing issues download the file via
+  command line **or** remove the ``quarantine`` attribute after downloading:
+  ``$ xattr -dr com.apple.quarantine borg-macosx64.tgz``)
 * **FreeBSD**: 10.2 (unknown whether it works for older releases)
 
 ARM binaries are built by Johann Bauer, see: https://borg.bauerj.eu/