Also account for EOL chars correctly in wxStyledTextCtrl::GetLineLength().

Make GetLineLength() consistent with GetLineText() after the changes of
r73140.

Closes #13646.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73150 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/stc/stc.h

@@ -4628,7 +4628,7 @@ public:
     // implement wxTextAreaBase pure virtual methods
     // ---------------------------------------------
 
-    virtual int GetLineLength(long n) const { return GetLine(n).length(); }
+    virtual int GetLineLength(long lineNo) const { return static_cast<int>(GetLineText(lineNo).length()); }
     virtual wxString GetLineText(long lineNo) const
     {
         wxString text = GetLine(static_cast<int>(lineNo));