Incorrect parsing of formula text

[nsk4]

Currently parser will fail to parse formulas from HTML correctly. See how the formula "0.1 mm (1⁄250 inch) to 1 metre (3.3 ft)" gets parsed from the following article:

• https://en.wikipedia.org/wiki/Flower
• https://en.wikipedia.org/api/rest_v1/page/html/Flower