SVN_SILENT made messages (.desktop file)
Minor: Cleanup includes
Fix crash in DUChain::addDocumentChain

BUG: 333477
Merge remote-tracking branch 'origin/1.6'

Conflicts:
	language/duchain/duchain.cpp
Don't add QJSON to public link interface

Not needed
Remove the slowest iterations of the quickopen benchmarks

This made the test shaky on CI (esp. in KF5) since it has a timeout
of 120 seconds.
A base expression visitor class for dynamically-typed languages.

This is potentially useful for Python, PHP, JS and Ruby.
For documentation on what it does, see the docs in the header file.
It's not a lot of shared functionality, but it is a piece of shared /
suggested architecture which makes it a) easier to write new language
plugins because there is a clear path for solving this problem; and b)
easier to understand other language plugin's architecture, because they
all work similar.