Revert "Add Documentation for Execution Results Handling in Clang-Repl (#65650)"

This reverts commit b9b8fc4.

This uses a function defined in LLVM's config-ix inside clang.
config-ix is a non-exported cmake module, so this is a layering
violation.

Author: nikic

clang/docs/CMakeLists.txt

@@ -103,13 +103,6 @@ function (gen_rst_file_from_td output_file td_option source docs_targets)
 endfunction()
 
 if (LLVM_ENABLE_SPHINX)
-  llvm_find_program(dot)
-  if (HAVE_DOT)
-    set(DOT ${LLVM_PATH_DOT})
-  else()
-    message(FATAL_ERROR "Cannot find DOT")
-  endif()
-
   include(AddSphinxTarget)
   if (SPHINX_FOUND AND (${SPHINX_OUTPUT_HTML} OR ${SPHINX_OUTPUT_MAN}))
     # Copy rst files to build directory before generating the html