Add some more docs

src/startest.gleam

@@ -3,20 +3,32 @@ import startest/runner
 import startest/test_case.{type Test, Test}
 import startest/test_tree.{type TestTree, Suite}
 
+/// Defines a new test suite with the given name.
+///
+/// A suite is a way of grouping related tests together.
+///
+/// `describe`s may also be nested in other `describe`s to form a hierarchy of tests.
 pub fn describe(name: String, suite: List(TestTree)) -> TestTree {
   Suite(name, suite)
 }
 
+/// Defines a test with the given name.
 pub fn it(name: String, body: fn() -> Nil) -> TestTree {
   Test(name, body, False)
   |> test_tree.Test
 }
 
+/// Skips a test defined using `it`.
+///
+/// This can be used to skip running certain tests, but without deleting the code.
+/// For instance, you might want to do this if a test is flaky and you want to stop
+/// running it temporarily until it can be fixed.
 pub fn xit(name: String, _body: fn() -> Nil) -> TestTree {
   Test(name, fn() { Nil }, True)
   |> test_tree.Test
 }
 
+/// Runs the given tests and reports results using the provided list of `Reporter`s.
 pub fn run_tests(tests: List(TestTree), reporters: List(Reporter)) -> Nil {
   runner.run_tests(tests, reporters)
 }