Update Scintilla.md

Update scintilla via the NPP project. Modified files:

via https://github.com/notepad-plus-plus/notepad-plus-plus/commit/d7819cf601051510b7fa1640ca17fedad297e1f8

• Upgrade Scintilla from v4.2.0 to v4.4.6

at https://github.com/notepad-plus-plus/notepad-plus-plus/commits/master?before=a044cefe7ce2bd8baba38ca6bcee8e5b50c7928a+35&branch=master

to https://github.com/KnIfER/Textrument/commit/12830a11fa5333194a649474bfc3f99255f0183a

• Merge: Make tab splitter menu and incremental search translatable

scintilla\boostregex\BoostRegExSearch.cxx
scintilla\include\Scintilla.h
scintilla\src\CellBuffer.cxx
scintilla\src\CellBuffer.h
scintilla\src\Document.h
scintilla\src\Editor.cxx
scintilla\src\SplitVector.h
scintilla\win32\SciLexer.vcxproj
scintilla\win32\cleanup.bat