feat(releasepr): release PRs can be updated

- PR Description
- Read prefix+suffix from PR description and put into changelog
- Keep those overrides on PR description changes
- Add pending level to new PRs

internal/markdown/extensions/ast/section.go

@@ -0,0 +1,32 @@
+package ast
+
+import (
+	gast "github.com/yuin/goldmark/ast"
+)
+
+// A Section struct represents a section of elements.
+type Section struct {
+	gast.BaseBlock
+	Name string
+}
+
+// Dump implements Node.Dump.
+func (n *Section) Dump(source []byte, level int) {
+	m := map[string]string{
+		"Name": n.Name,
+	}
+	gast.DumpHelper(n, source, level, m, nil)
+}
+
+// KindSection is a NodeKind of the Section node.
+var KindSection = gast.NewNodeKind("Section")
+
+// Kind implements Node.Kind.
+func (n *Section) Kind() gast.NodeKind {
+	return KindSection
+}
+
+// NewSection returns a new Section node.
+func NewSection(name string) *Section {
+	return &Section{Name: name}
+}