学习Git，坚持“git merge --no-ff feature / signup-form”

Question

我正在通过一个Git教程，它要求我使用--no-ff选项合并这个文件，但现在我被困在这样的地方：

    Mackenzies-MacBook-Pro:learn-git Mackenzie$ git merge --no-ff feature/signup-form

Merge branch 'feature/signup-form'
added signup

# Please enter a commit message to explain why this merge is necessary,
# especially if it merges an updated upstream into a topic branch.
#
# Lines starting with '#' will be ignored, and an empty message aborts
# the commit.
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-- INSERT --

我不确定输入的位置和内容，教程根本不会引用它。