Update VE core submodule to master (2fc7855)

New changes:
95ee357 Copy annotation indexes before returning
91a5630 Localisation updates from https://translatewiki.net.
978e223 Function name fix
7558ed0 Add 'snowman' and '☃' in comment for greppability
af0e8b1 Localisation updates from https://translatewiki.net.
43e6144 CommentNode: Change icon from orange to grey
349cbec Update OOjs UI to v0.1.0-pre (e9cf571db2)
921103b Generate only one pair of snowmen for multi-sibling nodes

Change-Id: Ifa0009e9363fa39a2c5ef41a42410391ea4f4711