Init clang tidy (#195)

tests/data/clang_tidy/clice.toml

@@ -0,0 +1,6 @@
+### clice configuration
+
+[server]
+
+    # Enable clang-tidy diagnostics.
+    clang_tidy = true

tests/data/clang_tidy/main.cpp

@@ -0,0 +1,6 @@
+#include <iostream>
+
+int main() {
+    std::cout << "Hello World!" << std::endl;
+    return 0;
+}