ClangFormat: Enable plugin by default

... and remove the compile- and run-time warnings.
Users can easily opt out of using clang-format via the settings dialog
these days (globally and per project), so loading the plugin does no
harm.
As of b88b73d9c1, clang formatting should
work without our custom patch, so there is no need to warn against that
either.

Change-Id: I5336857c6e27d9162084c2dacf187acb0015dc6a
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Artem Sokolovskii <artem.sokolovskii@qt.io>
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/clangformat/clangformatplugin.cpp

@@ -127,25 +127,6 @@ bool ClangFormatPlugin::initialize(const QStringList &arguments, QString *errorS
                         openClangFormatConfigAction->setData(doc->filePath().toVariant());
                 });
     }
-#ifndef KEEP_LINE_BREAKS_FOR_NON_EMPTY_LINES_BACKPORTED
-#ifdef _MSC_VER
-#pragma message( \
-    "ClangFormat: building against unmodified Clang, see README.md for more info")
-#else
-#warning ClangFormat: building against unmodified Clang, see README.md for more info
-#endif
-    static const Id clangFormatFormatWarningKey = "ClangFormatFormatWarning";
-    if (!ICore::infoBar()->canInfoBeAdded(clangFormatFormatWarningKey))
-        return true;
-    InfoBarEntry
-        info(clangFormatFormatWarningKey,
-             tr("The ClangFormat plugin has been built against an unmodified Clang. "
-                "You might experience formatting glitches in certain circumstances. "
-                "See https://code.qt.io/cgit/qt-creator/qt-creator.git/tree/README.md for more "
-                 "information."),
-             InfoBarEntry::GlobalSuppression::Enabled);
-    ICore::infoBar()->addInfo(info);
-#endif
     return true;
 }