Rename WXTHREAD_XXX_PRIORITY yo wxPRIORITY_XXX.

This will allow to reuse the same constants for the process priorities in an
upcoming commit.

See #14931.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73405 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/defs.h

@@ -3383,5 +3383,13 @@ typedef const void* WXWidget;
 
 #endif /* !wxUSE_NO_MANIFEST && _MSC_FULL_VER >= 140040130 */
 
+/* wxThread and wxProcess priorities */
+enum
+{
+    wxPRIORITY_MIN     = 0u,   /* lowest possible priority */
+    wxPRIORITY_DEFAULT = 50u,  /* normal priority */
+    wxPRIORITY_MAX     = 100u  /* highest possible priority */
+};
+
 #endif
     /*  _WX_DEFS_H_ */