diet-ng 1.8.3: source/diet/internal/html.d:185: data modification (truncation) in filterHTMLEscape?

[kdevel]

The actual modification happens in the line marked as `(1)`. But 
this is not the location of the root cause.

The variable `ch` is of type `dchar`. Does anybody see the 
problem?

```d
     switch (ch) {
		default:
			if (flags & HTMLEscapeFlags.escapeUnknown) {
				dst.put("&#");
				dst.put(to!string(cast(uint)ch));
				dst.put(';');
			} else dst.put(ch);
			break;
		case '"':
			if (flags & HTMLEscapeFlags.escapeQuotes) dst.put(""");
			else dst.put('"');
			break;
		case '\'':
			if (flags & HTMLEscapeFlags.escapeQuotes) dst.put("'");
			else dst.put('\'');
			break;
		case '\r', '\n':
			if (flags & HTMLEscapeFlags.escapeNewline) {
				dst.put("&#");
				dst.put(to!string(cast(uint)ch));
				dst.put(';');
			} else dst.put(ch);
			break;
		case 'a': .. case 'z': goto case;
		case 'A': .. case 'Z': goto case;
		case '0': .. case '9': goto case;
		case ' ', '\t', '-', '_', '.', ':', ',', ';',
			 '#', '+', '*', '?', '=', '(', ')', '/', '!',
			 '%' , '{', '}', '[', ']', '`', '´', '$', '^', '~':
			dst.put(cast(char)ch); // <<----- (1)
			break;
		case '<': dst.put("<"); break;
		case '>': dst.put(">"); break;
		case '&': dst.put("&"); break;
	}
```

[1] 
https://github.com/rejectedsoftware/diet-ng/blob/master/source/diet/internal/html.d