Function generate_property 

pub fn generate_property(
    out: &mut String,
    prop: &PropertyInfo,
    pctx: &PropertyContext,
    ctx: &CodegenContext,
    suppress_setters: &HashSet<String>,
)

Generate a getter and setter for a single property (used as default impls in Ext trait).

Setters whose name appears in suppress_setters are skipped.