fix: hide keyline when footnotes are preceded by header (#4529)
fix: hide keyline when footnotes are preceded by header (#4529)

Hide key-line created by `markdown-it-footnote` template when footnotes are directly preceded by header.

Examples:
```md
# References
[^1]: Shows no key-line because References header has one already

# New Page
Text goes here and whatever else

[^1]: these footnotes have no preceding header and will show a key-line
```
Requarks/wiki,Requarks/wiki,Requarks/wiki,Requarks/wiki