Widget that displays a map for a specific [class@View].
`GtkSourceMap` is a widget that maps the content of a [class@View] into a smaller view so the user can have a quick overview of the whole
document.
This works by connecting a [class@View] to to the `GtkSourceMap` using the [property@Map:view] property or [method@Map.set_view].
`GtkSourceMap` is a [class@View] object. This means that you can add a [class@GutterRenderer] to a gutter in the same way you would for a
[class@View]. One example might be a [class@GutterRenderer] that shows which lines have changed in the document.
Additionally, it is desirable to match the font of the `GtkSourceMap` and the [class@View] used for editing. Therefore, [
property@Map:font-desc] should be used to set the target font. You will need to adjust this to the desired font size for the map. A 1pt
font generally seems to be an appropriate font size. "Monospace 1" is the default. See [method@Pango.FontDescription.set_size] for how to
alter the size of an existing [struct@Pango.FontDescription].
When FontConfig is available, `GtkSourceMap` will try to use a bundled "block" font to make the map more legible.
