docs(_included_ssh_config_files): note max recursion depth origin

Author: scop

bash_completion

@@ -2130,7 +2130,10 @@ _included_ssh_config_files()
     local -a include_files
     included=("$configfile")
 
-    while ((${#included[@]} > 0 && depth++ < 16)); do
+    # Max recursion depth per openssh's READCONF_MAX_DEPTH:
+    # https://github.com/openssh/openssh-portable/blob/5ec5504f1d328d5bfa64280cd617c3efec4f78f3/readconf.c#L2240
+    local max_depth=16
+    while ((${#included[@]} > 0 && depth++ < max_depth)); do
         _comp_split include_files "$(command sed -ne 's/^[[:blank:]]*[Ii][Nn][Cc][Ll][Uu][Dd][Ee][[:blank:]]\(.*\)$/\1/p' "${included[@]}")" || return
         included=()
         for i in "${include_files[@]}"; do