[K2] Inconsistent documentable rendering order

[IgnatBeresnev]

The sorting order of documentables is not consistent between K1 and K2 implementations

Questions:

• Should we sort documentables right after analysis or before rendering?
• What should be sorted?
• How they should be sorted - which order for functions, constructors, etc? Maybe it should be a separate issue

Is it blocking?

• Testing: no
• Beta release: no
• Full release: more like yes than no