[GH-19267] Spelling comments (#19268)

* spelling: comments

Signed-off-by: Josh Soref <jsoref@users.noreply.github.com>
Co-authored-by: Josh Soref <jsoref@users.noreply.github.com>
Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

app/post.go

@@ -299,7 +299,7 @@ func (a *App) CreatePost(c *request.Context, post *model.Post, channel *model.Ch
 	rPostCopy := rpost.Clone()
 
 	// FIXME: Removes PreviewPost from the post payload sent to the MessageHasBeenPosted hook so that plugins compiled with older versions of
-	// Mattermost—without the gob registeration of the PreviewPost struct—won't crash.
+	// Mattermost—without the gob registration of the PreviewPost struct—won't crash.
 	if rPostCopy.Metadata != nil {
 		rPostCopy.Metadata = rPostCopy.Metadata.Copy()
 	}