enable customizing exercise numbering

README.md

@@ -18,7 +18,7 @@ A summary is then printed on the front page.
 
 ## Usage
 
-Writing an exam is now easy:
+Writing an exam is now easy (see [API](#api) for all options):
 
     #import "@local/exam:0.1.0": exam, exercise, exercise-items, mtext
 
@@ -99,3 +99,34 @@ These are used in the example above.
 - `mtext(str)` to typeset text within math mode using the default text font.
 - `frame(stroke_width)` provides `stroke` for use in a `table`, horizontal lines only,
 top and bottom lines are bold.
+
+### API
+
+```typ
+exam(
+  title: "%KLAUSUR or EXAM%",
+
+  course-title: [%COURSE_TITLE_FIRST_LINE% \ %COURSE_TITLE_SECOND_LINE%],
+  course-short-title: "%course-short-title%",
+  course-code: "%course-code%",
+
+  date: "%DATE%",
+
+  institution: smallcaps("NAWI Graz"),
+
+  duration-minutes: "%DURATION%",
+
+  ask-student-number: false,
+  ask-trainer-name: false,
+  ask-group: true,
+
+  instructions: none,
+
+  language: "de", // or "en"
+  font-size: 12pt,
+  paper-size: "a4",
+
+  exercise-numbering: "1",
+)
+```
+