Replace F extension with string interpolation

OpenRA.Mods.Common/Terrain/DefaultTileCache.cs

@@ -99,8 +99,7 @@ namespace OpenRA.Mods.Common.Terrain
 					var start = indices.Min();
 					var end = indices.Max();
 					if (start < 0 || end >= frameCount)
-						throw new YamlException("Template `{0}` uses frames [{1}..{2}] of {3}, but only [0..{4}] actually exist"
-							.F(t.Key, start, end, i, frameCount - 1));
+						throw new YamlException($"Template `{t.Key}` uses frames [{start}..{end}] of {i}, but only [0..{frameCount - 1}] actually exist");
 
 					variants.Add(indices.Select(j =>
 					{