[fractal/fractal-next] Pretty print the event source

[Julian Sparber <jsparber src gnome org>]

commit 4e37a95445d3a7a6f9a2c06fe4963976e68afb2e
Author: Kévin Commaille <zecakeh tedomum fr>
Date:   Mon Nov 1 20:37:40 2021 +0100

    Pretty print the event source

 src/session/room/event.rs | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)
---
diff --git a/src/session/room/event.rs b/src/session/room/event.rs
index d9c7253f..04a4c39e 100644
--- a/src/session/room/event.rs
+++ b/src/session/room/event.rs
@@ -235,8 +235,21 @@ impl Event {
 
     pub fn source(&self) -> String {
         let priv_ = imp::Event::from_instance(self);
-        serde_json::to_string_pretty(priv_.pure_event.borrow().as_ref().unwrap().event.json())
-            .unwrap()
+
+        // We have to convert it to a Value, because a RawValue cannot be pretty-printed.
+        let json: serde_json::Value = serde_json::from_str(
+            priv_
+                .pure_event
+                .borrow()
+                .as_ref()
+                .unwrap()
+                .event
+                .json()
+                .get(),
+        )
+        .unwrap();
+
+        serde_json::to_string_pretty(&json).unwrap()
     }
 
     pub fn timestamp(&self) -> DateTime {