chore: vendor nucleo-ext + fork, so we can depend on our changes properly (#3284)

We cannot publish to crates.io without specifying a version, and we
cannot do that without properly forking nucleo. We're shipping
atuin-nucleo, but will likely drop this if we can get our changes
upstream. This is highlighted in the README + manifest, and the original
author is still included.

Originally forked here: https://github.com/atuinsh/nucleo-ext

cc @BinaryMuse - this should just be a vendor + restructure, but would
appreciate the sanity check

## Checks
- [ ] I am happy for maintainers to push small adjustments to this PR,
to speed up the review cycle
- [ ] I have checked that there are no existing pull requests for the
same thing

1 files changed, 13 insertions, 0 deletions

diff --git a/crates/atuin-nucleo/matcher/generate_case_fold_table.sh b/crates/atuin-nucleo/matcher/generate_case_fold_table.sh
new file mode 100755
index 00000000..32a26697
--- /dev/null
+++ b/crates/atuin-nucleo/matcher/generate_case_fold_table.sh
@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+set -e
+
+dir=$(pwd)
+mkdir /tmp/ucd-15.0.0
+cd /tmp/ucd-15.0.0
+curl -LO https://www.unicode.org/Public/zipped/15.0.0/UCD.zip
+unzip UCD.zip
+
+cd "${dir}"
+cargo install ucd-generate
+ucd-generate case-folding-simple /tmp/ucd-15.0.0 --chars > src/chars/case_fold.rs
+rm -rf /tmp/ucd-15.0.0