build: update doxygen

TODO

@@ -30,3 +30,4 @@ TODO:
 * any cdynamic to support const ownership construction
 * allow passing arguments to meta setter/getter (we can fallback on meta invoke probably)
 * FetchContent_Populate -> FetchContent_MakeAvailable warnings
+* doc: IMPLICIT_DIR_DOCS for dir docs or \dir

docs/CMakeLists.txt

@@ -1,6 +1,6 @@
 # Doxygen configuration (documentation)
 
-find_package(Doxygen 1.10)
+find_package(Doxygen 1.13)
 
 if(DOXYGEN_FOUND)
     include(FetchContent)
@@ -51,9 +51,9 @@ if(DOXYGEN_FOUND)
     )
 
     if(ENTT_INSTALL)
-    install(
-        DIRECTORY ${DOXY_OUTPUT_DIRECTORY}/html
-        DESTINATION share/${PROJECT_NAME}-${PROJECT_VERSION}/
-    )
-endif()
+        install(
+            DIRECTORY ${DOXY_OUTPUT_DIRECTORY}/html
+            DESTINATION share/${PROJECT_NAME}-${PROJECT_VERSION}/
+        )
+    endif()
 endif()