Scaling both imperial and metric measurements

[ddbrain]

Is your new feature related to a problem? Please describe.
Currently when using the scaling feature only the imperial measurement is scaled when a measurement includes both imperial and metric. such as "1 teaspoon (2 grams) salt" becomes "2 teaspoons (2 grams) salt"

Describe the solution you'd like
It would be nice if the scaling tool could recognize both the imperial and metric measurements and scale both. Making the above example at 2x scale converted to "2 teaspoons (4 grams) salt"

[julianpoy]

Definitely could be added. The regex simply doesn't check for a second set of measurements in parenthesis after the originating measurement. Shouldn't be too hard, but does conflict with some of the improvements here: #1078. I'll take a look and see if I can add support there.