docs(tvix/eval): Use correct syntax for module doc comments

Change-Id: I35741856f34b86a538f226a8eaf8806edede60ec
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6207
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI

tvix/eval/src/value/attrs.rs

@@ -1,10 +1,10 @@
-/// This module implements Nix attribute sets. They have flexible
+//! This module implements Nix attribute sets. They have flexible
-/// backing implementations, as they are used in very versatile
+//! backing implementations, as they are used in very versatile
-/// use-cases that are all exposed the same way in the language
+//! use-cases that are all exposed the same way in the language
-/// surface.
+//! surface.
-///
+//!
-/// Due to this, construction and management of attribute sets has
+//! Due to this, construction and management of attribute sets has
-/// some peculiarities that are encapsulated within this module.
+//! some peculiarities that are encapsulated within this module.
 use std::collections::btree_map;
 use std::collections::BTreeMap;
 use std::fmt::Display;

tvix/eval/src/value/list.rs

@@ -1,4 +1,4 @@
-/// This module implements Nix lists.
+//! This module implements Nix lists.
 use std::fmt::Display;
 
 use super::Value;

tvix/eval/src/value/string.rs

@@ -1,10 +1,9 @@
+//! This module implements Nix language strings and their different
+//! backing implementations.
 use smol_str::SmolStr;
 use std::hash::Hash;
 use std::{borrow::Cow, fmt::Display};
 
-/// This module implements Nix language strings and their different
-/// backing implementations.
-
 #[derive(Clone, Debug)]
 enum StringRepr {
     Smol(SmolStr),

tvix/eval/src/warnings.rs

@@ -1,5 +1,5 @@
-/// Warnings are emitted in cases where code passed to Tvix exhibits
+//! Implements warnings that are emitted in cases where code passed to
-/// problems that the user could address.
+//! Tvix exhibits problems that the user could address.
 
 #[derive(Debug)]
 pub enum WarningKind {