Update VE core submodule to master (26a1027)

New changes:
ed97f51 Localisation updates from https://translatewiki.net.
9382cb7 Localisation updates from https://translatewiki.net.
f3c057b Update OOjs UI to v0.1.0-pre (527ad0ee5a)
db83b1d Localisation updates from https://translatewiki.net.
cf8463e Add a function to ElementLinearData to count all elements that aren't in internalList

Change-Id: I1e07568b1c094d96d4ec8ab1af50b242f77346d6
Fix reference dialog apply button disabling when modifying existing reference

Existing references keep internal records of current saved data, which breaks
the current length check. Instead, use the new function to count all
*non-internal* elements

Relies on I8ecbf387
Related to bug 52182

Change-Id: I4b9bb866babe018d75dc083fab35375b9fb53d3c