Escape more strings: formspecs, item descriptions, infotexts...

Also, change the escape character to the more standard \x1b
Thus, it can be used in the future for translation or colored text,
for example.

src/util/string.h

@@ -386,14 +386,6 @@ inline void str_replace(std::string &str, const std::string &pattern,
 	}
 }
 
-/**
- * Remove all chat escape sequences in \p s.
- *
- * @param s The string in which to remove escape sequences.
- * @return \p s, with escape sequences removed.
- */
-std::wstring removeChatEscapes(const std::wstring &s);
-
 /**
  * Replace all occurrences of the character \p from in \p str with \p to.
  *
@@ -476,7 +468,7 @@ inline std::string wrap_rows(const std::string &from,
  * Removes backslashes from an escaped string (FormSpec strings)
  */
 template <typename T>
-inline std::basic_string<T> unescape_string(std::basic_string<T> &s)
+inline std::basic_string<T> unescape_string(const std::basic_string<T> &s)
 {
 	std::basic_string<T> res;
 
@@ -492,6 +484,40 @@ inline std::basic_string<T> unescape_string(std::basic_string<T> &s)
 	return res;
 }
 
+/**
+ * Remove all escape sequences in \p s.
+ *
+ * @param s The string in which to remove escape sequences.
+ * @return \p s, with escape sequences removed.
+ */
+template <typename T>
+std::basic_string<T> unescape_enriched(const std::basic_string<T> &s)
+{
+	std::basic_string<T> output;
+	size_t i = 0;
+	while (i < s.length()) {
+		if (s[i] == '\x1b') {
+			++i;
+			if (i == s.length()) continue;
+			if (s[i] == '(') {
+				++i;
+				while (i < s.length() && s[i] != ')') {
+					if (s[i] == '\\') {
+						++i;
+					}
+					++i;
+				}
+				++i;
+			} else {
+				++i;
+			}
+			continue;
+		}
+		output += s[i];
+		++i;
+	}
+	return output;
+}
 
 /**
  * Checks that all characters in \p to_check are a decimal digits.