docs: fix hyphenation updater script name (#1931)

## Summary

* Rename the hyphenation update script to match the documented
`update_hyphenation.sh` name.
* Update the hyphenation trie documentation command example to use the
renamed script.

## Additional Context

The prose in `docs/hyphenation-trie-format.md` referred to
`update_hyphenation.sh`, but the command example and file on disk used
`update_hypenation.sh`. This made the documented script name
inconsistent with the runnable command.

Verified with `rg` that no references to the misspelled script name
remain. Also ran `bash -n scripts/update_hyphenation.sh` to syntax-check
the renamed script without downloading trie files.

scripts/update_hyphenation.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+
+cd "$ROOT_DIR"
+
+process() {
+  local lang="$1"
+
+  mkdir -p "build"
+  wget -O "build/$lang.bin" "https://github.com/typst/hypher/raw/refs/heads/main/tries/$lang.bin"
+
+  python scripts/generate_hyphenation_trie.py \
+    --input "build/$lang.bin" \
+    --output "lib/Epub/Epub/hyphenation/generated/hyph-${lang}.trie.h"
+}
+
+process en
+process fr
+process de
+process es
+process ru
+process it
+process uk