@Nonnull
	public static RegexRule addLanguage(@Nonnull String name, @Nonnull InputStream stream) throws IOException {
		try {
			RegexRule lang = GSON.fromJson(new InputStreamReader(stream), RegexRule.class);
			NAME_TO_LANG.put(name, lang);
			return lang;
		} catch (Exception ex) {
			// Gson's exceptions are unchecked, so rethrow as checked.
			throw new IOException(ex.getMessage(), ex);
		}
	}
Adds support for the language.

@param name
		Language name to use as a key. Will be used in {@link #getLanguages()} and {@link #getLanguage(String)}.
@param stream
		Input stream to file to parse.

@return Language root rule.

@throws IOException
		When the file cannot be read or mapped into the rule structure.
@see LanguageStylesheets#addLanguage(String, String) You should assign a stylesheet by the same language name.
recaf-ui/src/main/java/software/coley/recaf/ui/control/richtext/syntax/RegexLanguages.java