Resolves a text style against the active theme (role defaults, font weight lookup, theme colours) and returns a `grid::gpar()`. Use it to draw text in theme styles inside a custom [new_block()].
Examples
text_gpar(text_style(weight = 600, color = "muted"))
#> bodybuildr: no weight-600 face found for "sans"; using bold.
#> $fontfamily
#> [1] "sans"
#>
#> $fontsize
#> [1] 9
#>
#> $col
#> [1] "#5B6472"
#>
#> $lineheight
#> [1] 1.45
#>
#> $font
#> bold
#> 2
#>