Utils: Modernize further

Many issues, mostly in headers, were not addressed in
e38410b76c

modernize-use-auto
modernize-use-nullptr
modernize-use-override
modernize-use-using
modernize-use-default-member-init
modernize-use-equals-default

Change-Id: I320a51726db881e582b898948d53735ebb06887a
Reviewed-by: hjk <hjk@qt.io>

src/libs/utils/textfileformat.cpp

@@ -68,10 +68,7 @@ QDebug operator<<(QDebug d, const TextFileFormat &format)
     as strings or string lists and to write out files.
 */
 
-TextFileFormat::TextFileFormat() :
-    lineTerminationMode(NativeLineTerminator), hasUtf8Bom(false), codec(nullptr)
-{
-}
+TextFileFormat::TextFileFormat() = default;
 
 /*!
     Detects the format of text data.