odoc: Fix formatting of paragraphs in lists (#2607)

The boxing of paragraphs was wrong in heavy-syntax lists:

    (** Lists can't be nested
        {ul
         {- foo }
         {- module
            system
            documentation
            including
            + bar
            + baz
         }
        } *)

CHANGES.md

@@ -105,6 +105,7 @@ profile. This started with version 0.26.0.
 - Display `a##b` instead of `a ## b` and similarly for operators that start with # (#2580, @v-gb)
 - \* Fix arrow type indentation with `break-separators=before` (#2598, @Julow)
 - Fix missing parentheses around a let in class expressions (#2599, @Julow)
+- Fix formatting of paragraphs in lists in documentation (#2607, @Julow)
 
 ## 0.26.2 (2024-04-18)
 

lib/Fmt_odoc.ml

@@ -268,7 +268,7 @@ let rec fmt_inline_elements c elements =
 
 and fmt_nestable_block_element c elm =
   match elm.Loc.value with
-  | `Paragraph elems -> fmt_inline_elements c elems
+  | `Paragraph elems -> hovbox 0 (fmt_inline_elements c elems)
   | `Code_block (s1, s2) -> fmt_code_block c s1 s2
   | `Math_block s -> fmt_math_block s
   | `Verbatim s -> fmt_verbatim_block ~loc:elm.location s

test/passing/tests/doc_comments-no-parse-docstrings.mli.ref

@@ -641,3 +641,12 @@ type x =
 (** at@ *)
 
 (** \@at *)
+
+(** Lists can't be nested
+    - foo
+    - module system documentation including
+    {ol
+    {- bar}
+    {- baz}
+    }
+*)

test/passing/tests/doc_comments-no-wrap.mli.ref

@@ -683,3 +683,12 @@ type x =
 (** at@ *)
 
 (** \@at *)
+
+(** Lists can't be nested
+    {ul
+     {- foo }
+     {- module system documentation including
+        + bar
+        + baz
+     }
+    } *)

test/passing/tests/doc_comments.mli

@@ -648,3 +648,12 @@ type x =
 
 (** at@ *)
 (** \@at *)
+
+(** Lists can't be nested
+    - foo
+    - module system documentation including
+    {ol
+    {- bar}
+    {- baz}
+    }
+*)

test/passing/tests/doc_comments.mli.ref

@@ -677,3 +677,12 @@ type x =
 (** at@ *)
 
 (** \@at *)
+
+(** Lists can't be nested
+    {ul
+     {- foo }
+     {- module system documentation including
+        + bar
+        + baz
+     }
+    } *)