D14122: KFormat: Replace unicode literal with unicode codepoint to fix MSVC build

[Stefan Brüns]

bruns added a dependency: D14121: KFormat: Add unit tests for mili/micro SI 
prefixes.

REPOSITORY
  R244 KCoreAddons

REVISION DETAIL
  https://phabricator.kde.org/D14122

To: bruns, #frameworks, kossebau, bcooksley
Cc: kde-frameworks-devel, michaelh, ngraham, bruns