R6 method for ExTera: list current templates in library.
$list_templates()Examples
tera <- new_engine()
tera$add_string_templates(
"hello-world" = '<p>Hello {{ x }}. This is {{ y }}.</p>',
"img-src" = '<img src="{{ img_src }}">'
)
tera$list_templates()
#> [1] "hello-world" "img-src"