book: add makefile step to remove arrow keys from book js

doc/Makefile

@@ -14,6 +14,7 @@ all: $(JSONRPC)
 	./generate_seminar_ics.py --ics
 	$(MAKE) -C ../ rustdoc
 	cp -r ../target/doc/* book/development/
+	./remove_chapter_nav_js.py
 
 $(DARKFID_JSONRPC):
 	@echo "# darkfid JSON-RPC API" > $@

doc/remove_chapter_nav_js.py

@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+
+# cp book/book.js /tmp/
+# python remove_chapter_nav_js.py
+# diff book/book.js /tmp/book.js
+
+with open("book/book.js") as f:
+    lines = f.read()
+
+lines = lines.split("\n")
+
+pre = []
+while True:
+    line = lines[0]
+
+    if "chapterNavigation()" in line:
+        break
+
+    pre.append(lines.pop(0))
+
+# chapterNavigation() {
+lines.pop(0)
+
+i = 1
+while True:
+    line = lines.pop(0)
+    i += line.count("{") - line.count("}")
+    assert i >= 0
+    if i == 0:
+        break
+
+src = "\n".join(pre + lines)
+#print(src)
+
+with open("book/book.js", "w") as f:
+    f.write(src)