improve emoji code parsing

Fix #129

src/internal/parser.ts

@@ -626,12 +626,15 @@ export const language = P.createLanguage({
 	},
 
 	emojiCode: r => {
+		const side = P.notMatch(P.regexp(/[a-z0-9]/i));
 		const mark = P.str(':');
 		return P.seq([
+			P.alt([P.lineBegin, side]),
 			mark,
 			P.regexp(/[a-z0-9_+-]+/i),
 			mark,
-		], 1).map(name => M.EMOJI_CODE(name as string));
+			P.alt([P.lineEnd, side]),
+		], 2).map(name => M.EMOJI_CODE(name as string));
 	},
 
 	link: r => {

test/parser.ts

@@ -34,7 +34,19 @@ describe('SimpleParser', () => {
 
 		it('between texts', () => {
 			const input = 'foo:bar:baz';
-			const output = [TEXT('foo'), EMOJI_CODE('bar'), TEXT('baz')];
+			const output = [TEXT('foo:bar:baz')];
+			assert.deepStrictEqual(mfm.parseSimple(input), output);
+		});
+
+		it('between texts 2', () => {
+			const input = '12:34:56';
+			const output = [TEXT('12:34:56')];
+			assert.deepStrictEqual(mfm.parseSimple(input), output);
+		});
+
+		it('between texts 3', () => {
+			const input = 'あ:bar:い';
+			const output = [TEXT('あ'), EMOJI_CODE('bar'), TEXT('い')];
 			assert.deepStrictEqual(mfm.parseSimple(input), output);
 		});
 	});