Memoize Y-offset for pawn rendering

Matrix4x4.rotation and Quaternion.eulerAngles are, somewhat confusingly,
not fields but relatively costly property accessors. When rendering many
pawns, repeated calls to them can have a measurable impact, so store the
result in a local variable and reuse it.

Source/CombatExtended/Harmony/Harmony_PawnRenderer.cs

@@ -60,11 +60,13 @@ private static void DrawMesh(Mesh mesh, Matrix4x4 matrix, Material mat, int laye
                 muzzleJump = -muzzleJump;
                 casingOffset.x *= -1;
             }
-            matrix.SetTRS(position + posVec.RotatedBy(matrix.rotation.eulerAngles.y) + recoilOffset, Quaternion.AngleAxis(matrix.rotation.eulerAngles.y + muzzleJump, Vector3.up), scale);
+
+            float yAngle = matrix.rotation.eulerAngles.y;
+            matrix.SetTRS(position + posVec.RotatedBy(yAngle) + recoilOffset, Quaternion.AngleAxis(yAngle + muzzleJump, Vector3.up), scale);
             CompEquippable compEquippable = eq.TryGetComp<CompEquippable>();
             if (compEquippable != null && compEquippable.PrimaryVerb is Verb_ShootCE verbCE)
             {
-                verbCE.drawPos = casingDrawPos + (casingOffset + posVec).RotatedBy(matrix.rotation.eulerAngles.y);
+                verbCE.drawPos = casingDrawPos + (casingOffset + posVec).RotatedBy(yAngle);
             }
             if (eq is WeaponPlatform platform)
             {