Fix #1486: update macOS instructions for chksum plugin

diff --git a/plugins/chksum b/plugins/chksum
index 06da799502038d0a88fa93561de34d488640c6fc..5fa91cbf8df1d31fc51e88359db15f569cd8b203 100755 (executable)
--- a/plugins/chksum
+++ b/plugins/chksum
@@ -2,7 +2,8 @@
 
 # Description: Create and verify checksums
 #
-# Note:  On macOS, install the relevant checksum packages from Homebrew.
+# Note:  On macOS, install the relevant checksum packages from Homebrew with:
+#            brew install coreutils
 #
 # Details:
 #   - selection: it will generate one file with the checksums and filenames