fix(extmarks): missing "spell" and "conceal" in details (#27116)

src/nvim/decoration.c

@@ -975,6 +975,9 @@ void decor_to_dict_legacy(Dictionary *dict, DecorInline decor, bool hl_name)
   if (sh_hl.hl_id) {
     PUT(*dict, "hl_group", hl_group_name(sh_hl.hl_id, hl_name));
     PUT(*dict, "hl_eol", BOOLEAN_OBJ(sh_hl.flags & kSHHlEol));
+    priority = sh_hl.priority;
+  }
+
   if (sh_hl.flags & kSHConceal) {
     char buf[MAX_SCHAR_SIZE];
     schar_get(buf, sh_hl.text[0]);
@@ -987,9 +990,6 @@ void decor_to_dict_legacy(Dictionary *dict, DecorInline decor, bool hl_name)
     PUT(*dict, "spell", BOOLEAN_OBJ(false));
   }
 
-    priority = sh_hl.priority;
-  }
-
   if (sh_hl.flags & kSHUIWatched) {
     PUT(*dict, "ui_watched", BOOLEAN_OBJ(true));
   }

test/functional/api/extmark_spec.lua

@@ -1639,6 +1639,40 @@ describe('API/extmarks', function()
         right_gravity = true,
       },
     }, get_extmark_by_id(ns, marks[3], { details = true }))
+    set_extmark(ns, marks[4], 0, 0, {
+      end_col = 1,
+      conceal = 'a',
+      spell = true,
+    })
+    eq({
+      0,
+      0,
+      {
+        conceal = 'a',
+        end_col = 1,
+        end_right_gravity = false,
+        end_row = 0,
+        ns_id = 1,
+        right_gravity = true,
+        spell = true,
+      },
+    }, get_extmark_by_id(ns, marks[4], { details = true }))
+    set_extmark(ns, marks[5], 0, 0, {
+      end_col = 1,
+      spell = false,
+    })
+    eq({
+      0,
+      0,
+      {
+        end_col = 1,
+        end_right_gravity = false,
+        end_row = 0,
+        ns_id = 1,
+        right_gravity = true,
+        spell = false,
+      },
+    }, get_extmark_by_id(ns, marks[5], { details = true }))
     api.nvim_buf_clear_namespace(0, ns, 0, -1)
     -- legacy sign mark includes sign name
     command('sign define sign1 text=s1 texthl=Title linehl=LineNR numhl=Normal culhl=CursorLine')