[examples][1ptracer][doc_config] do not inclue problems etc to main page

examples/1ptracer/.doc_config

 {
     "README.md" : [
         "doc/intro.md",
-        "spatialparams_1p.hh",
-        "problem_1p.hh",
-        "properties_1p.hh",
-        "spatialparams_tracer.hh",
-        "problem_tracer.hh",
-        "properties_tracer.hh",
         "main.cc",
+        "doc/problems.md",
         "doc/results.md"
     ]
 }