[cmake] Always generate compile_commands.json

I can't think of a valid reason not to generate compile_commands.json
and several reasons why we should

1. I don't like typing configure options that much.
2. I like editor completion to work without me having to regenerate my
   build.
3. It's a good way to inspect final build flags without having to
   query the build system.

CMakeLists.txt

@@ -53,6 +53,9 @@ set(UR_CONFORMANCE_TARGET_TRIPLES "" CACHE STRING
     "List of sycl targets to build CTS device binaries for")
 set(UR_CONFORMANCE_AMD_ARCH "" CACHE STRING "AMD device target ID to build CTS binaries for")
 
+# There's little reason not to generate the compile_commands.json
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
 include(Assertions)
 
 set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)