fix(_command_offset): fix completions splitted by spaces

Author: akinomyoga

bash_completion

@@ -2297,7 +2297,9 @@ _comp_command_offset()
             else
                 cspec=${cspec#complete}
                 cspec=${cspec%%@("$compcmd"|"'${compcmd//\'/\'\\\'\'}'")}
-                COMPREPLY=($(eval compgen "$cspec" -- '$cur'))
+                local result=$(eval compgen "$cspec" -- '$cur')
+                local IFS=$'\n'
+                COMPREPLY=($result)
             fi
             break
         done