Doc: Qt Core: Fully qualify \variable documentation

Upcoming changes to QDoc require API entities to be fully qualified;
previously, QDoc maintained a list of 'open namespaces' that were
part of matching the documented entity with its declaration, but
that concept does not work for parallelized parsing where the order
of processing can be arbitrary.

Change-Id: If8f84df4f429ef92c861d6094e58448bd658a540
Reviewed-by: Luca Di Sera <luca.disera@qt.io>

src/corelib/io/qzip.cpp

@@ -730,37 +730,37 @@ void QZipWriterPrivate::addEntry(EntryType type, const QString &fileName, const
 */
 
 /*!
-    \variable FileInfo::filePath
+    \variable QZipReader::FileInfo::filePath
     The full filepath inside the archive.
 */
 
 /*!
-    \variable FileInfo::isDir
+    \variable QZipReader::FileInfo::isDir
     A boolean type indicating if the entry is a directory.
 */
 
 /*!
-    \variable FileInfo::isFile
+    \variable QZipReader::FileInfo::isFile
     A boolean type, if it is one this entry is a file.
 */
 
 /*!
-    \variable FileInfo::isSymLink
+    \variable QZipReader::FileInfo::isSymLink
     A boolean type, if it is one this entry is symbolic link.
 */
 
 /*!
-    \variable FileInfo::permissions
+    \variable QZipReader::FileInfo::permissions
     A list of flags for the permissions of this entry.
 */
 
 /*!
-    \variable FileInfo::crc
+    \variable QZipReader::FileInfo::crc
     The calculated checksum as a crc type.
 */
 
 /*!
-    \variable FileInfo::size
+    \variable QZipReader::FileInfo::size
     The total size of the unpacked content.
 */