Update doc about single-file-modding to state that it also applies to variants.
@@ -58,8 +58,8 @@ Constraints:
* All modifies templates must have signatures that are compatible with the
modifiable template.
* Calls can only be made to the modifiable template.
-* A single Soy file can only modify templates from a single external
- namespace, excluding variants.
+* A single Soy file can only modify templates from a single external namespace
+ (ie, a single file).
## Variants
