docs(ref): Simplify default-members wording

This will make it easier to make future changes

Author: epage

src/doc/src/reference/workspaces.md

@@ -127,7 +127,7 @@ a [virtual workspace](#virtual-workspace), it will apply to all members (as if
 
 ## The `default-members` field
 
-The `default-members` key can be specified to set the members to
+The `default-members` field specifies the members to
 operate on when in the workspace root and the package selection flags are not
 used: