elixir-替换unicode字符-PCRE不支持\L、\L、\N{name}、\U或\U

我正在尝试从字符串中删除不可见的字符

看见 remove-zero-width-space-characters

iex> str = "\uFEFF<?xml>"
iex> String.replace(str, ~r/[\u200B\u200C\u200D\uFEFF]/, "")   
** (Regex.CompileError) PCRE does not support \L, \l, \N{name}, \U, or \u at position 1
    (elixir) lib/regex.ex:171: Regex.compile!/2
    (elixir) expanding macro: Kernel.sigil_r/2
    iex:44: (file)

错误: PCRE does not support \L, \l, \N{name}, \U, or \u at position 1

如何实现上述正则表达式?

注意:当使用字符串代替正则表达式时,它可以工作,但为了代码效率,我想使用正则表达式

iex(34)> String.replace(a, "\uFEFF", "")
"<?xml>"