MS word object model browse mode: native selection mode is on by defa…

…ult a and cannot be turned off, so ensure the toggle message reflects this. (#16151)

Follow up from #16129
Fixes #16097

Summary of the issue:
Selecting text in Browse mode in Microsoft Word moves the physical selection. Thus it is the equivalent to native selection mode. Pr #16129 ensured that Browse mode in MS word with UI Automation took this into account and made the toggle message report that native selection mode could not be turned off. However this has not been done for MS Word object model, and NVDA states that native selection mode is unsupported.

Description of user facing changes
When trying to toggle native selection mode in Browse mode in MS Word when not using UI Automation, NvDA will correctly state that native selection mode cannot be turned off.
When copying text with control+c in browse mode in MS Word when not using UI Automation, formatting is now also copied.
Description of development approach
Set browse mode for MS Word object model's _nativeAppSelectionMode to True.

source/NVDAObjects/window/winword.py

@@ -1167,6 +1167,7 @@ def _get_focusableNVDAObjectAtStart(self):
 class WordDocumentTreeInterceptor(browseMode.BrowseModeDocumentTreeInterceptor):
 
 	TextInfo=BrowseModeWordDocumentTextInfo
+	_nativeAppSelectionMode = True
 
 	def _activateLongDesc(self,controlField):
 		longDesc=controlField.get('longdescription')