Fix descending sort for character data

[krlmlr]

options(conflicts.policy = list(warn = FALSE))
library(duckplyr)

Sys.setenv("DUCKPLYR_FORCE" = "TRUE")

data.frame(a = letters[1:3]) |>
  as_duckplyr_df() |>
  arrange(desc(a))
#> Error: Binder Error: No function matches the given name and argument types '-(VARCHAR)'. You might need to add explicit type casts.
#>  Candidate functions:
#>  -(TINYINT) -> TINYINT
#>  -(TINYINT, TINYINT) -> TINYINT
#>  -(SMALLINT) -> SMALLINT
#>  -(SMALLINT, SMALLINT) -> SMALLINT
#>  -(INTEGER) -> INTEGER
#>  -(INTEGER, INTEGER) -> INTEGER
#>  -(BIGINT) -> BIGINT
#>  -(BIGINT, BIGINT) -> BIGINT
#>  -(HUGEINT) -> HUGEINT
#>  -(HUGEINT, HUGEINT) -> HUGEINT
#>  -(FLOAT) -> FLOAT
#>  -(FLOAT, FLOAT) -> FLOAT
#>  -(DOUBLE) -> DOUBLE
#>  -(DOUBLE, DOUBLE) -> DOUBLE
#>  -(DECIMAL) -> DECIMAL
#>  -(DECIMAL, DECIMAL) -> DECIMAL
#>  -(UTINYINT) -> UTINYINT
#>  -(UTINYINT, UTINYINT) -> UTINYINT
#>  -(USMALLINT) -> USMALLINT
#>  -(USMALLINT, USMALLINT) -> USMALLINT
#>  -(UINTEGER) -> UINTEGER
#>  -(UINTEGER, UINTEGER) -> UINTEGER
#>  -(UBIGINT) -> UBIGINT
#>  -(UBIGINT, UBIGINT) -> UBIGINT
#>  -(DATE, DATE) -> BIGINT
#>  -(DATE, INTEGER) -> DATE
#>  -(TIMESTAMP, TIMESTAMP) -> INTERVAL
#>  -(INTERVAL, INTERVAL) -> INTERVAL
#>  -(DATE, INTERVAL) -> DATE
#>  -(TIME, INTERVAL) -> TIME
#>  -(TIMESTAMP, INTERVAL) -> TIMESTAMP
#>  -(INTERVAL) -> INTERVAL

^{Created on 2024-02-04 with reprex v2.1.0}