Missing translation for group members

**Describe the bug**

Here:
https://github.com/bookwyrm-social/bookwyrm/blob/c6858a598f4c42bf231103017beb0f903642e1f3/bookwyrm/templates/groups/members.html#L6

Is missing a translation block

**To Reproduce**
See above 

**Expected behavior**
String should be translatable

**Screenshots**
N/A

**Instance**
all

**Additional context**
N/A
