Add group functions from the Console API

src/console_ffi.mjs

···
 export function clear() {
   console.clear();
 }
+
+export function group(label) {
+  console.group(label);
+}
+
+export function group_collapsed(label) {
+  console.groupCollapsed(label);
+}
+
+export function group_end() {
+  console.groupEnd();
+}

src/plinth/javascript/console.gleam

···
 /// and will have no effect (and no error).
 @external(javascript, "../../console_ffi.mjs", "clear")
 pub fn clear() -> Nil
+
+/// Creates a new inline group in the Web console log,
+/// causing any subsequent console messages to be indented by an additional level,
+/// until `console.group_end` is called.
+@external(javascript, "../../console_ffi.mjs", "group")
+pub fn group(label: String) -> Nil
+
+/// reates a new inline group in the console. Unlike `console.group`, however,
+/// the new group is created collapsed. The user will need to use the disclosure
+/// button next to it to expand it, revealing the entries created in the group.
+///
+/// Call `console.group_end` to back out to the parent group.
+@external(javascript, "../../console_ffi.mjs", "group_collapsed")
+pub fn group_collapsed(label: String) -> Nil
+
+/// Exits the current inline group in the console
+@external(javascript, "../../console_ffi.mjs", "group_end")
+pub fn group_end() -> Nil

test/javascript/node/console_test.gleam

···
 pub fn assert_fail_test() {
   console.assert_(False, "You should see this!")
 }
+
+pub fn group_test() {
+  console.group("test label")
+  console.log("Inside the group")
+  console.log("Also inside the group")
+  console.group_end()
+  console.log("Outside the group")
+}