fix crate_name attribute description
@@ -132,7 +132,7 @@ name of the crate with the [_MetaNameValueStr_] syntax.
```
The crate name must not be empty, and must only contain [Unicode alphanumeric]
-or `-` (U+002D) characters.
+or `_` (U+005F) characters.
[^phase-distinction]: This distinction would also exist in an interpreter.
Static checks like syntactic analysis, type checking, and lints should
