Diaspora: Editing of all text entities is in progress
A frequently-raised concern (and one of my own frustrations) with Diaspora is the inability to edit posts or comments after they've been submitted. There is a feature request with a long discussion thread, dating to 2011, hashing out all they whys and why-nots of this.
And that's moot. The feature has been coded and ... will eventually be merged (though most recent activity is February 21, 2018).
Stay tuned.