add fish script, configure it to start up js instead of python

typst-documentation.fish

@@ -0,0 +1,26 @@
+#!/usr/bin/env fish
+
+function html_to_md
+    set -l filename $argv[1]
+    set -l filename_md $(basename $filename .html).md
+    echo "transforming $filename => $filename_md..."
+    pandoc -f html -t markdown $filename -o $filename_md
+end
+
+# funcsave html_to_md # uncomment only for the first run / when this function changes
+
+function main
+    if not type -q bun
+        echo "bun is not installed"
+        return 1
+    end
+
+    rm typst-docs/*
+    bun index.ts
+    cd typst-docs
+    parallel -j 8 html_to_md ::: (ls -1)
+    cat *.md > DOCUMENTATION.md
+    cd ../
+end
+
+main