[WIP] Create "substring" match type

[MilesCranmer]

This is a WIP. It does not yet seem to trigger the desired behavior so I am trying to debug this.

Description

Similar behavior to zsh's history-substring-search method, this matching algorithm will check if a given string is contained within the other, regardless of position.

• The zsh version of this: https://github.com/zsh-users/zsh-history-substring-search
• This PR should close History substring search #7968

User-Facing Changes

• This adds the "substring" match type, so users can turn on a history-substring-search

Tests + Formatting

• These need to be implemented. I wanted to get people's thoughts first as it might change how I need to write the test.

After Submitting

[MilesCranmer]

Actually maybe I'm implementing this in the wrong spot... @fdncred Where is the history up/down prefix matching done?

[MilesCranmer]

Looks like https://github.com/nushell/reedline/blob/46f410bfdce0b64c3d94fdc0271886f30d64b151/src/history/base.rs#L13 is what is needed in reedline. So just need the right config to enable this?

[MilesCranmer]

It basically looks like all we need to do is to set the Reedline object to have its history_cursor field equal to a HistoryCursor object with field query equal to HistoryNavigationQuery::SubstringSearch(String).

So where is the Reedline object created?

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Edit: or maybe this has to be done by mapping "up" to ReedlineEvent::HistorySearch??

[fdncred]

Usually to implement things like this, it requires a change to reedline and a change to nushell. Following your comments, some of this could already be done (it looks like substring is already in reedline as per your link). You'll have to experiment to see what works.

One way that I test this type of stuff is using the example demo in reedline or setup an additional example in reedline to show how to use your changes.

[MilesCranmer]

Ok this might take me a while longer to figure out. I'll just mention that if anybody wants to have a go at this instead, please be my guest!