[gnome-calculator] Fixed currency conversion using the convert button (fixes #216)

[Robert Roth <robertroth src gnome org>]

commit 58726bfec29e2c5f316209e3fafd48f2678582bf
Author: Robert Roth <robert roth off gmail com>
Date:   Fri Mar 26 01:10:04 2021 +0200

    Fixed currency conversion using the convert button (fixes #216)

 lib/unit.vala | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/lib/unit.vala b/lib/unit.vala
index c442b4f4..417b55c0 100644
--- a/lib/unit.vala
+++ b/lib/unit.vala
@@ -381,7 +381,8 @@ public class Unit : Object
 
     public string get_symbol_from_format ()
     {
-        return _format.replace ("%s", "").replace (" ", "");
+        return _name;
+        // return _format.replace ("%s", "").replace (" ", "");
     }
 
     public bool matches_symbol (string symbol, bool case_sensitive = true)