Use startsWith and endsWith for readability

src/mfm/parse/core/syntax-highlighter.ts

@@ -197,7 +197,7 @@ const elements: Element[] = [
 
 		if (thisIsNotARegexp) return null;
 		if (regexp == '') return null;
-		if (regexp[0] == ' ' && regexp[regexp.length - 1] == ' ') return null;
+		if (regexp.startsWith(' ') && regexp.endsWith(' ')) return null;
 
 		return {
 			html: `<span class="regexp">/${escape(regexp)}/</span>`,

src/mfm/parse/elements/hashtag.ts

@@ -10,7 +10,7 @@ export type TextElementHashtag = {
 
 export default function(text: string, i: number) {
 	if (!(/^\s#[^\s]+/.test(text) || (i == 0 && /^#[^\s]+/.test(text)))) return null;
-	const isHead = text[0] == '#';
+	const isHead = text.startsWith('#');
 	const hashtag = text.match(/^\s?#[^\s]+/)[0];
 	const res: any[] = !isHead ? [{
 		type: 'text',

src/mfm/parse/elements/link.ts

@@ -13,7 +13,7 @@ export type TextElementLink = {
 export default function(text: string) {
 	const match = text.match(/^\??\[([^\[\]]+?)\]\((https?:\/\/[\w\/:%#@\$&\?!\(\)\[\]~\.=\+\-]+?)\)/);
 	if (!match) return null;
-	const silent = text[0] == '?';
+	const silent = text.startsWith('?');
 	const link = match[0];
 	const title = match[1];
 	const url = match[2];