Merge pull request doxygen#12229 from albert-github/feature/bug_config_doc_internal

Remove obsolete `DOT_MULTI_TARGETS` from docs_internal

Author: doxygen

doc_internal/Doxyfile.in

@@ -359,7 +359,6 @@ PLANTUML_INCLUDE_PATH  =
 PLANTUMLFILE_DIRS      =
 DOT_GRAPH_MAX_NODES    = 300
 MAX_DOT_GRAPH_DEPTH    = 0
-DOT_MULTI_TARGETS      = YES
 GENERATE_LEGEND        = YES
 DOT_CLEANUP            = NO
 MSCGEN_TOOL            =