update docs

[maelle]

Go through C/igraph's changelog, and update R docs for all functions that changed in 0.10.

[maelle]

potentially relevant #840 (comment)

[krlmlr]

From #1071.

[maelle]

How could we make this a bit easier? Something to extract info from the C release notes somehow?

[schochastics]

That is a very good question. If not automated, we probably need to make this a recurring task for each release (like check contributers)?

[krlmlr]

We could ask our most productive team members for help. Also, lumen?

[maelle]

lumen?

[schochastics]

https://github.com/jnsahaj/lumen