Inline formatters should add quotes if whitespace at start end

eg. I think 

``` r
x <- "weird-name "
cli::cli_text("The name is {.file {x}}")
#> The name is weird-name
```

should yield:

``` r
x <- "weird-name "
cli::cli_text("The name is {.file {x}}")
#> The name is 'weird-name '
```