update coding-style.txt

docs/coding-style.txt

@@ -8,7 +8,7 @@ Every script MUST start with a shebang pointing to /bin/sh
 
 	#!/bin/sh
 
-This ensures the script is shell-agnostic (unless you're weird and symlinked /bin/fish to /bin/sh)
+This ensures the script is shell-agnostic (unless you're weird and symlinked some POSIX-incompatible shell to /bin/sh)
 
 2 - Functions