[fxtf-drafts] [css-masking] Percentage for clip-path should be n/a or clarification is needed

lahmatiy has just created a new issue for https://github.com/w3c/fxtf-drafts:

== [css-masking] Percentage for clip-path should be n/a or clarification is needed ==
Currently percentage for `clip-path` is defined as:
```
Percentages:	as specified
```
It's unclear what does it mean. Looks like a mistake and should be changed to:
```
Percentages:	n/a
```

Please view or discuss this issue at https://github.com/w3c/fxtf-drafts/issues/155 using your GitHub account