Remove mentions of C++11 in docs

Since wxWidgets now requires C++11 it's not necessary to point
out C++11 features as such explicitly.

interface/wx/atomic.h

@@ -16,8 +16,8 @@
 /**
     This function increments @a value in an atomic manner.
 
-    @note It is recommended to use @c std::atomic available in C++11 and later
-    instead of this function in any new code.
+    @note It is recommended to use @c std::atomic instead of this function in
+    any new code.
 
     Whenever possible wxWidgets provides an efficient, CPU-specific,
     implementation of this function. If such implementation is available, the

interface/wx/cmdline.h

@@ -212,7 +212,7 @@ struct wxCmdLineEntryDesc
     }
     @endcode
 
-    With C++11, the for loop could be written:
+    The for loop could be written:
     @code
     for (const auto &arg : parser.GetArguments()) {
         // working on arg as with *itarg above

interface/wx/dialog.h

@@ -630,7 +630,7 @@ public:
         passed as the argument upon completion, instead of generating the
         wxEVT_WINDOW_MODAL_DIALOG_CLOSED event.
 
-        This form is particularly useful in combination with C++11 lambdas,
+        This form is particularly useful in combination with lambdas,
         when it allows writing window-modal very similarly to how ShowModal()
         is used (with the notable exception of not being able to create
         the dialog on stack):

interface/wx/event.h

@@ -550,7 +550,7 @@ public:
          threads, but that the method will be always called in the main, GUI,
          thread context.
 
-         This overload is particularly useful in combination with C++11 lambdas:
+         This overload is particularly useful in combination with lambdas:
          @code
          wxGetApp().CallAfter([]{
              wxBell();

interface/wx/grid.h

@@ -2212,21 +2212,12 @@ struct wxGridBlockDiffResult
     Note that objects of this class can only be returned by wxGrid, but not
     constructed in the application code.
 
-    The preferable way to iterate over it is using C++11 range-for loop:
+    The preferable way to iterate over it is using range-for loop:
     @code
         for ( const auto& block: grid->GetSelectedBlocks() ) {
             ... do something with block ...
         }
     @endcode
-    When not using C++11, iteration has to be done manually:
-    @code
-        wxGridBlocks range = grid->GetSelectedBlocks();
-        for ( wxGridBlocks::iterator it = range.begin();
-              it != range.end();
-              ++it ) {
-            ... do something with *it ...
-        }
-    @endcode
 
     @since 3.1.4
  */
@@ -5024,7 +5015,7 @@ public:
     /**
         Returns a range of grid selection blocks.
 
-        The returned range can be iterated over, e.g. with C++11 range-for loop:
+        The returned range can be iterated over, e.g. with range-for loop:
         @code
             for ( const auto block: grid->GetSelectedBlocks() ) {
                 if ( block.Intersects(myBlock) )

interface/wx/statbox.h

@@ -167,8 +167,7 @@ public:
         checkbox stays enabled even if @c box->Enable(false) is called.
 
         However with the actual behaviour, implemented in this overridden
-        method, the following code (shown using C++11 only for convenience,
-        this behaviour is not C++11-specific):
+        method, the following code:
         @code
             auto check = new wxCheckBox(parent, wxID_ANY, "Use the box");
             auto box = new wxStaticBox(parent, wxID_ANY, check);

interface/wx/thread.h

@@ -188,7 +188,7 @@ public:
         return wxCOND_NO_ERROR;
         @endcode
 
-        The predicate would typically be a C++11 lambda:
+        The predicate would typically be a lambda:
         @code
         condvar.Wait([]{return value == 1;});
         @endcode

interface/wx/webview.h

@@ -576,7 +576,6 @@ public:
     handler provided URLs.
 
     This backend is not enabled by default, to build it follow these steps:
-    - Visual Studio 2015 or newer, or GCC/Clang with c++11 is required
     - With CMake just enable @c wxUSE_WEBVIEW_EDGE
     - When not using CMake:
         - Download the <a href="https://aka.ms/webviewnuget">WebView2 SDK</a>