Remove the flag wxSTC_FIND_CXX11REGEX from wxSTC docs

wxSTC is currently built without c++11 regex support, but the search
flag wxSTC_FIND_CXX11REGEX was included with wxSTC any way. This commit
modifies gen_iface.py so that this flag will no longer be generated or
documented. To prevent any code that is currently using this flag from
being broken, the flag is manually defined in stc.h.in.

In short, the flag will be preserved as it currently is but will be
undocumented so users won't mistakenly try to use it.

src/stc/gen_iface.py

@@ -78,7 +78,8 @@ notMappedSciValues = set([
     'INDIC0_MASK',
     'INDIC1_MASK',
     'INDIC2_MASK',
-    'INDICS_MASK'
+    'INDICS_MASK',
+    'SCFIND_CXX11REGEX'
 ])
 
 # Map some generic typenames to wx types, using return value syntax

src/stc/stc.h.in

@@ -124,6 +124,14 @@ class WXDLLIMPEXP_FWD_CORE wxScrollBar;
 
 #endif // WXWIN_COMPATIBILITY_3_0
 
+// wxSTC is currently built without c++11 regex support, but the search flag
+// wxSTC_FIND_CXX11REGEX was included with wxSTC any way. gen_iface.py has since
+// been changed so that this flag will no longer be generated or documented,
+// but the flag is preserved here so that any code using the flag before
+// gen_iface.py was changed will not be broken.
+
+#define wxSTC_FIND_CXX11REGEX 0x00800000
+
 //----------------------------------------------------------------------
 // Commands that can be bound to keystrokes section {{{