config: increase default output ratelimit

For full screen terminals it is common for scrolling through vim
to hit the prior default limit.  This value feels better.  This
comes at the cost of an increased delay for eg: CTRL-C processing
in the case where something is spamming the terminal, but that
is relatively rare.

src/config/mod.rs

@@ -847,7 +847,7 @@ fn default_ratelimit_line_prefetches_per_second() -> u32 {
 }
 
 fn default_ratelimit_output_bytes_per_second() -> u32 {
-    200_000
+    400_000
 }
 
 fn default_true() -> bool {