Node description as changes to the graph

[omaranwar85]

Hi,

Adding description to nodes is not registered as changes made to the graph. Saving the graph after, results in a file with bigger size on the disk, and description is also available after reload. Just need that "*" as a reminder to user to save the graph after adding the description.

Regards
Omar

Version: v6.7.0
Commit Hash: 23f5d29