build: add missing \

Author: skypjack

.github/workflows/tools.yml

@@ -48,8 +48,8 @@ jobs:
       working-directory: build
       run: |
         export PATH=$PATH:${GITHUB_WORKSPACE}/build/include-what-you-use/build/bin
-        cmake -DBUILD_TESTING=ON
-              -Dlibuv_buildtests=OFF
+        cmake -DBUILD_TESTING=ON \
+              -Dlibuv_buildtests=OFF \
               -DCMAKE_C_COMPILER=clang-$LLVM \
               -DCMAKE_CXX_COMPILER=clang++-$LLVM \
               -DCMAKE_CXX_INCLUDE_WHAT_YOU_USE="include-what-you-use;-Xiwyu;--mapping_file=${GITHUB_WORKSPACE}/uvw.imp;-Xiwyu;--no_fwd_decls;-Xiwyu;--verbose=1" \