允许插入多个元素在指定列表元素之前 allow insert multiple elements before specified list element

[iamqiz]

Is your feature request related to a problem? Please describe.
我想在第一个列表元素之前插入2个新元素
I want to insert 2 new list elements before first list element ,
我是这么写的:
so i use following patch:

patch:
    engine/translators/@before 0: "lua_translator@aa_translator"
    engine/translators/@before 0: "lua_translator@bb_translator"

但是这只插入了一个元素
but this only insert 1 element into list

Describe the solution you'd like
希望增加一个新的patch语法@insertBefore n,n可以是0 1 2 ... last,
add a new patch syntax, @insertBefore n , the n can be 0,1,2 ...last
它可以在索引为n的元素前插入多个新元素
it will insert multiple elements before the element that has index n

patch:
  engine/translators/@insertBefore 0: 
    - "lua_translator@aa_translator"
    - "lua_translator@bb_translator"

类似/+,但是它可以在列表任意地方插入多个元素(除了在列表结尾)
like /+, but it can insert multiple element anythere (except at the ending of list)
这个语法将会是/+的完美补充
@insertBefore n will be a perfect supplement of /+
感谢!
thanks!

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