Ability to set limit of items displayed before "Show more" is used

# Feature request

## Summary
In the Search Bar, 2nd level expand, Tcl has many commands. I would like all to display w/o a "Show more..." clickable to get the rest. Request config option to allow setting the threshold for "Show more..." (or number-at-a-time before next Show more prompt). Thanks!

Start at the Search Bar's second-level expansion and locate the existing "Show more..." behavior for Tcl commands. Trace how the current item threshold is chosen, then make that threshold configurable and verify that the requested number of items appears before another prompt.

索引モデルが issue の本文から書いたものです。