Editor code: tidy up BOOLs,NULLs and overrides pt5. (#2876)

A few 'typedefs' replaced by 'using's
This shouldn't have any functional changes at all, just c++17 modernization
It's a part 5 of a split #2847

Signed-off-by: Nemerle <nemerle5+git@gmail.com>

Co-authored-by: Nemerle <nemerle5+git@gmail.com>

Code/Editor/CryEditDoc.h

@@ -26,7 +26,7 @@ struct ICVar;
 
 // Filename of the temporary file used for the hold / fetch operation
 // conform to the "$tmp[0-9]_" naming convention
-#define HOLD_FETCH_FILE "$tmp_hold" 
+#define HOLD_FETCH_FILE "$tmp_hold"
 
 class CCryEditDoc
     : public QObject
@@ -36,7 +36,7 @@ class CCryEditDoc
     Q_PROPERTY(bool modified READ IsModified WRITE SetModifiedFlag);
     Q_PROPERTY(QString pathName READ GetLevelPathName WRITE SetPathName);
     Q_PROPERTY(QString title READ GetTitle WRITE SetTitle);
- 
+
 public: // Create from serialization only
     enum DocumentEditingMode
     {
@@ -82,7 +82,7 @@ public: // Create from serialization only
 
     bool DoSave(const QString& pathName, bool replace);
     SANDBOX_API bool Save();
-    virtual BOOL DoFileSave();
+    virtual bool DoFileSave();
     bool SaveModified();
 
     virtual bool BackupBeforeSave(bool bForce = false);
@@ -102,7 +102,7 @@ public: // Create from serialization only
     bool IsLevelExported() const;
     void SetLevelExported(bool boExported = true);
 
-    BOOL CanCloseFrame();
+    bool CanCloseFrame();
 
     enum class FetchPolicy
     {
@@ -144,7 +144,7 @@ protected:
     };
     bool BeforeOpenDocument(const QString& lpszPathName, TOpenDocContext& context);
     bool DoOpenDocument(TOpenDocContext& context);
-    virtual BOOL LoadXmlArchiveArray(TDocMultiArchive& arrXmlAr, const QString& absoluteLevelPath, const QString& levelPath);
+    virtual bool LoadXmlArchiveArray(TDocMultiArchive& arrXmlAr, const QString& absoluteLevelPath, const QString& levelPath);
     virtual void ReleaseXmlArchiveArray(TDocMultiArchive& arrXmlAr);
 
     virtual void Load(TDocMultiArchive& arrXmlAr, const QString& szFilename);