Fix UI string: remove placeholders for arguments
Summary:
%1, %2,... are interpreted as placeholders for arguments leading to
an I18n_ARGUMENT_MISSING error in the visible string. Rewrite them
as more generic placeholder which are not replaced, as it was done
for other strings in the same file.
Test Plan:
When accessing the configuration of 'Diff & Merge', "What's this"
on "External diff display", there is no more I18n_ARGUMENT_MISSING
error.
Reviewers: chehrlic, lueck
Reviewed By: chehrlic, lueck
Subscribers: lueck, Localization
Tags: Localization, Subversion Client (KDE SVN)
Differential Revision: https://phabricator.kde.org/D4356