bump crengine: various fixes, improved Russian typography

[poire-z]

Includes:

• Various in-page footnotes, tables and covers fixes and tweaks crengine#558 :
• In-page footnotes: avoid with '-cr-hint: noteref-ignore'
• In-page footnotes: ensure they don't cross "flows"
• Tables: fix rendering when negative text-indent
• FB2 cover drawing: ensure _invertImages flag
  Closes dark mode makes picture in book negative (inverted) #11574.
• EPUB: fallback to look for a cover in the first fragment
  Closes Cover image cannot be displayed #11571.
• TextLang: Russian: add typography rules Add typography rules for Russian crengine#557

Also update to libunibreak 6.1.

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This change is 

[poire-z]

@Frenzie : is there a way to fetch nightlies/build artifacts, even when the nightly server bandwidth is exceeded ?
https://gitlab.com/koreader/nightly-builds/-/pipelines (where I used to download them) seems to be stopped and not provide anything when that happens (nothing in the history for the last downtime period 19/2 to 26/2).

[Frenzie]

@poire-z Nightlies are triggered by the server that's down right now, but if you have an account on GitLab I'll add you so you can trigger the pipeline (or individual builds) yourself.

Edit: I just started one btw.

[poire-z]

Oh, thanks - I do have an account there, I had just forgotten how all this works :)
(I think I can, and did in the past, trigger pipelines.)