Use wxTimer::StartOnce() instead of wxTIMER_ONE_SHOT

This is more readable and shorter, so encourage using this form.

No real changes.

interface/wx/timer.h

@@ -126,8 +126,8 @@ public:
 
         To make your code more readable you may also use the following symbolic constants:
         - wxTIMER_CONTINUOUS: Start a normal, continuously running, timer
-        - wxTIMER_ONE_SHOT: Start a one shot timer
-        Alternatively, use StartOnce().
+        - wxTIMER_ONE_SHOT: Start a one shot timer. Alternatively, and
+        preferably, call StartOnce() instead of this function.
 
         If the timer was already running, it will be stopped by this method before
         restarting it.

samples/stc/stctest.cpp

@@ -668,7 +668,7 @@ AppAbout::AppAbout (wxWindow *parent,
     m_timer = nullptr;
     if (milliseconds > 0) {
         m_timer = new wxTimer (this, myID_ABOUTTIMER);
-        m_timer->Start (milliseconds, wxTIMER_ONE_SHOT);
+        m_timer->StartOnce(milliseconds);
     }
 
     // Get version of Scintilla

src/generic/listctrl.cpp

@@ -3168,7 +3168,7 @@ void wxListMainWindow::OnChar( wxKeyEvent &event )
 
                 // Notice that we should start the timer even if we didn't find
                 // anything to make sure we reset the search state later.
-                m_findTimer->Start(wxListFindTimer::DELAY, wxTIMER_ONE_SHOT);
+                m_findTimer->StartOnce(wxListFindTimer::DELAY);
 
                 // restart timer even when there's no match so bell get's reset
                 if ( item != (size_t)-1 )

src/generic/treectlg.cpp

@@ -3389,7 +3389,7 @@ void wxGenericTreeCtrl::OnChar( wxKeyEvent &event )
 
                 // Notice that we should start the timer even if we didn't find
                 // anything to make sure we reset the search state later.
-                m_findTimer->Start(wxTreeFindTimer::DELAY, wxTIMER_ONE_SHOT);
+                m_findTimer->StartOnce(wxTreeFindTimer::DELAY);
 
                 if ( id.IsOk() )
                 {