update tests with non-top header

tests/suite/layout/grid/headers.typ

@@ -118,16 +118,12 @@
 )
 
 --- grid-header-not-at-first-row ---
-// Error: 3:3-3:19 header must start at the first row
-// Hint: 3:3-3:19 remove any rows before the header
 #grid(
   [a],
   grid.header([b])
 )
 
 --- grid-header-not-at-first-row-two-columns ---
-// Error: 4:3-4:19 header must start at the first row
-// Hint: 4:3-4:19 remove any rows before the header
 #grid(
   columns: 2,
   [a],
@@ -463,8 +459,6 @@
 #table(
   columns: 3,
   [Outside],
-  // Error: 1:3-4:4 header must start at the first row
-  // Hint: 1:3-4:4 remove any rows before the header
   table.header(
     [A], table.cell(x: 1)[B], [C],
     table.cell(x: 1)[D],

tests/suite/layout/grid/subheaders.typ

@@ -0,0 +1,24 @@
+--- grid-subheaders ---
+#set page(width: auto, height: 12em)
+#let rows(n) = {
+  range(n).map(i => ([John \##i], table.cell(stroke: green)[123], table.cell(stroke: blue)[456], [789], [?], table.hline(start: 4, end: 5, stroke: red))).flatten()
+}
+#table(
+  columns: 5,
+  align: center + horizon,
+  table.header(
+    table.cell(colspan: 5)[*Cool Zone*],
+  ),
+  table.header(
+    level: 2,
+    table.cell(stroke: red)[*Name*], table.cell(stroke: aqua)[*Number*], [*Data 1*], [*Data 2*], [*Etc*],
+    table.hline(start: 2, end: 3, stroke: yellow)
+  ),
+  ..rows(6),
+  table.header(
+    level: 2,
+    table.cell(stroke: red)[*New Name*], table.cell(stroke: aqua, colspan: 4)[*Other Data*],
+    table.hline(start: 2, end: 3, stroke: yellow)
+  ),
+  ..rows(5)
+)