feat: add str_ilike() support

[edward-burn]

closes #1810

@krlmlr hopefully this is a useful addition, and will match the upcoming dbplyr release

library(dplyr, warn.conflicts = FALSE)
library(stringr)
library(dbplyr, warn.conflicts = FALSE)
library(duckdb)
#> Loading required package: DBI

con <- DBI::dbConnect(duckdb(), path = ":memory:")
test_data <- data.frame(var = "A")
db_test_data <- copy_to(con, test_data, overwrite = TRUE)
db_test_data  %>%
  dplyr::mutate(m_1 = str_ilike(var, "a"),
                m_2 = str_like(var, "a")) |> 
  dplyr::show_query()
#> <SQL>
#> SELECT test_data.*, var ILIKE 'a' AS m_1, var LIKE 'a' AS m_2
#> FROM test_data
db_test_data  %>%
  dplyr::mutate(m_1 = str_ilike(var, "a"),
                m_2 = str_like(var, "a"))
#> # Source:   SQL [?? x 3]
#> # Database: DuckDB 1.4.3-dev218 [root@Darwin 24.6.0:R 4.5.2/:memory:]
#>   var   m_1   m_2  
#>   <chr> <lgl> <lgl>
#> 1 A     TRUE  FALSE

^{Created on 2025-12-05 with reprex v2.1.1}

[krlmlr]

Thanks, looks good. Can you please add a test?

[edward-burn]

Thanks, looks good. Can you please add a test?

Sure, test now added

[krlmlr]

Thanks!