chore(docs): updates for R check notes (#295)

DESCRIPTION

@@ -1,20 +1,22 @@
 Package: polars
-Title: Polars ported to R
+Title: 'Polars' Ported to R
 Version: 0.6.1.9000
 Depends: R (>= 4.1.0)
 Imports: utils, codetools
 Authors@R:
   c(person("Ritchie", "Vink", , "[email protected]", role = c("aut")),
     person("Soren", "Welling", , "[email protected]", role = c("aut","cre")))
-Description: This package ports the polars data query library to R.
+Description: 'Polars' is a lightning fast Data Frame library written in Rust.
+  This package allows converting R data to 'Polars' data and vice versa,
+  and enabling fast data processing with 'Polars'.
 License: MIT + file LICENSE
 Encoding: UTF-8
 Roxygen: list(markdown = TRUE)
 RoxygenNote: 7.2.3
 URL: https://github.com/pola-rs/r-polars
     https://rpolars.r-universe.dev/polars
-Suggests: 
-    arrow, 
+Suggests:
+    arrow,
     bench,
     bit64,
     data.table,
@@ -40,7 +42,7 @@ Config/Needs/dev:
     robinlovelace/styler.equals,
     rextendr
 Config/testthat/edition: 3
-Collate: 
+Collate:
     'utils.R'
     'extendr-wrappers.R'
     'after-wrappers.R'

R/expr__expr.R

@@ -3,7 +3,7 @@
 #' @name Expr_class
 #' @description `Expr`essions are all the functions and methods that are applicable
 #' to a Polars DataFrame. They can be split into the following categories (following
-#' the [Py-Polars classification](https://pola-rs.github.io/polars/py-polars/html/reference/expressions)):
+#' the [Py-Polars classification](https://pola-rs.github.io/polars/py-polars/html/reference/expressions/)):
 #'  * Aggregate
 #'  * Binary
 #'  * Categorical