Refactoring a note with same headers only retains last split content

[dleeftink]

When applying the Split by headings command on the following note containing the same headings:

## Same header
Content A

## Same header
Content B

The refactored note only includes the 'Content B' rather than a concatenation of both. As such, content is lost during the refactoring.

[lynchjames]

This was also raised in #84.

A fix in 1.8.2 generates two separate files in this case with their respective content:

• Same header.md
• Same header2.md