doctum: add page (#5238)

pages/common/doctum.md

@@ -0,0 +1,24 @@
+# doctum
+
+> A PHP API documentation generator.
+> More information: <https://github.com/code-lts/doctum>.
+
+- Parse a project:
+
+`doctum parse`
+
+- Render a project:
+
+`doctum render`
+
+- Parse then render a project:
+
+`doctum update`
+
+- Parse and render only a specific version of a project:
+
+`doctum update --only-version={{version}}`
+
+- Parse and render a project using a specific configuration:
+
+`doctum update {{path/to/config.php}}`