Replace wxEXPLICIT with the 'explicit' keyword

See #17655.

include/wx/msw/private/comptr.h

@@ -25,7 +25,7 @@ public:
     {
     }
 
-    wxEXPLICIT wxCOMPtr(T* ptr)
+    explicit wxCOMPtr(T* ptr)
         : m_ptr(ptr)
     {
         if ( m_ptr )

include/wx/msw/private/pipestream.h

@@ -13,7 +13,7 @@
 class wxPipeInputStream : public wxInputStream
 {
 public:
-    wxEXPLICIT wxPipeInputStream(HANDLE hInput);
+    explicit wxPipeInputStream(HANDLE hInput);
     virtual ~wxPipeInputStream();
 
     // returns true if the pipe is still opened
@@ -34,7 +34,7 @@ protected:
 class wxPipeOutputStream: public wxOutputStream
 {
 public:
-    wxEXPLICIT wxPipeOutputStream(HANDLE hOutput);
+    explicit wxPipeOutputStream(HANDLE hOutput);
     virtual ~wxPipeOutputStream() { Close(); }
     bool Close();
 

include/wx/msw/private/textmeasure.h

@@ -19,13 +19,13 @@
 class wxTextMeasure : public wxTextMeasureBase
 {
 public:
-    wxEXPLICIT wxTextMeasure(const wxDC *dc, const wxFont *font = NULL)
+    explicit wxTextMeasure(const wxDC *dc, const wxFont *font = NULL)
         : wxTextMeasureBase(dc, font)
     {
         Init();
     }
 
-    wxEXPLICIT wxTextMeasure(const wxWindow *win, const wxFont *font = NULL)
+    explicit wxTextMeasure(const wxWindow *win, const wxFont *font = NULL)
         : wxTextMeasureBase(win, font)
     {
         Init();