[skip ci] Add some documentation for PR #3998

Signed-off-by: Alexis Jeandet <alexis.jeandet@member.fsf.org>

docs/markdown/Qt5-module.md

@@ -9,6 +9,7 @@ This method takes the following keyword arguments:
  - `moc_headers`, `moc_sources`, `ui_files`, `qresources`, which define the files that require preprocessing with `moc`, `uic` and `rcc`
  - `include_directories`, the directories to add to header search path for `moc` (optional)
  - `moc_extra_arguments`, any additional arguments to `moc` (optional). Available since v0.44.0.
+ - `dependencies`, dependency objects needed by moc. Available since v0.48.0.
  
 It returns an opaque object that should be passed to a main build target.
 
@@ -39,7 +40,8 @@ qt5_dep = dependency('qt5', modules: ['Core', 'Gui'])
 inc = include_directories('includes')
 moc_files = qt5.preprocess(moc_headers : 'myclass.h',
                            moc_extra_arguments: ['-DMAKES_MY_MOC_HEADER_COMPILE'],
-                           include_directories: inc)
+                           include_directories: inc,
+                           dependencies: qt5_dep)
 translations = qt5.compile_translations(ts_files : 'myTranslation_fr.ts', build_by_default : true)
 executable('myprog', 'main.cpp', 'myclass.cpp', moc_files,
            include_directories: inc,