qbs build: Fix linking ClangFormat on Windows

Apparently, the MSVC linker gets confused if an input library
("clangFormat.lib") has the (almost) same file name as an output library
("ClangFormat.lib"), even though the latter is specified with an
absolute path.

Change-Id: Ia76e60fd10e16ce8daff880f4005d40d7f20d08c
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/clangformat/clangformat.qbs

@@ -2,6 +2,7 @@ import qbs
 
 QtcPlugin {
     name: "ClangFormat"
+    targetName: "ClangFormatPlugin"
 
     Depends { name: "Core" }
     Depends { name: "TextEditor" }