Improve Index section detection

[davorpa]

Resolve this TODOS across localized files

free-programming-books-parser/index.js

Lines 178 to 192 in 5eaf00b

	// find where Index ends
	// probably could be done better, review later
	let i = 0,
	count = 0;
	for (i; i < tree.length; i++) {
	if (tree[i].type == "heading" && tree[i].depth == "3") count++;
	if (count == 2) break;
	}
	tree.slice(i).forEach((item) => {
	// Start iterating after Index
	try {
	if (item.type == "heading" && item.children[0].value == "Index") return;
	if (item.type == "heading") {

part of EbookFoundation/free-programming-books#6988 (comment)

Index word is not translated according to file locale. E.g.:

• Índice for -es.md files
• Índice for -pt_BR.md files
• 目录 for -zh.md files
• other variants at EbookFoundation/free-programming-books@78913af