@spec master_rels_xml(String.t()) :: String.t()

Generates the rels XML for the notes master (link to its own theme).

@spec master_xml() :: String.t()

Returns the notes master XML (python-pptx template embedded verbatim).

@spec theme_xml() :: String.t()

Returns the notes theme XML (separate theme for notes master, per python-pptx).

@spec to_xml(String.t()) :: String.t()

Generates the XML for a notes slide with the given text.

Each line of notes_text becomes its own paragraph, so the spacing the author typed is the spacing the reader sees in the notes pane. A blank line becomes an empty paragraph rather than being dropped.