delta-find: adjust the default candidate group chunk size
We move from 10 to 20 as the default as some usage in the wild saw a small
degradation in storage quality when using `10`.
--- a/mercurial/configitems.py Tue Feb 07 10:27:21 2023 +0100
+++ b/mercurial/configitems.py Thu Feb 23 15:16:40 2023 +0100
@@ -2058,7 +2058,7 @@
coreconfigitem(
b'storage',
b'revlog.delta-parent-search.candidate-group-chunk-size',
- default=10,
+ default=20,
)
coreconfigitem(
b'storage',