fix(patch, truncate): Get help correctly on macos

The usage output on macos is in bsd style, not gnu style

Author: yedayak

completions/patch

@@ -50,7 +50,11 @@ _comp_cmd_patch()
     [[ $was_split ]] && return
 
     if [[ $cur == -* ]]; then
-        _comp_compgen_help
+        if [[ $OSTYPE == "darwin*" ]]; then
+            _comp_compgen_usage
+        else
+            _comp_compgen_help
+        fi
         [[ ${COMPREPLY-} == *= ]] && compopt -o nospace
         return
     fi

completions/truncate

@@ -20,7 +20,11 @@ _comp_cmd_truncate()
     [[ $was_split ]] && return
 
     if [[ $cur == -* ]]; then
-        _comp_compgen_help
+        if [[ $OSTYPE == "darwin*" ]]; then
+            _comp_compgen_usage
+        else
+            _comp_compgen_help
+        fi
         [[ ${COMPREPLY-} == *= ]] && compopt -o nospace
         return
     fi