[MINOR][DOCS] Fix documentation for slide function

### What changes were proposed in this pull request?

This PR proposes to fix documentation for slide function. Fixed the spacing issue and added some parameter related info.

### Why are the changes needed?

Documentation improvement

### Does this PR introduce any user-facing change?

No (doc-only change).

### How was this patch tested?

Manually tested by documentation build.

Closes #26896 from bboutkov/pyspark_doc_fix.

Authored-by: Boris Boutkov <boris.boutkov@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
(cherry picked from commit 3bf5498)
Signed-off-by: HyukjinKwon <gurwls223@apache.org>

R/pkg/R/functions.R

@@ -3340,8 +3340,8 @@ setMethod("size",
 #' (array indices start at 1, or from the end if start is negative) with the specified length.
 #'
 #' @rdname column_collection_functions
-#' @param start an index indicating the first element occurring in the result.
-#' @param length a number of consecutive elements chosen to the result.
+#' @param start the starting index
+#' @param length the length of the slice
 #' @aliases slice slice,Column-method
 #' @note slice since 2.4.0
 setMethod("slice",

python/pyspark/sql/functions.py

@@ -1908,6 +1908,11 @@ def slice(x, start, length):
     """
     Collection function: returns an array containing  all the elements in `x` from index `start`
     (array indices start at 1, or from the end if `start` is negative) with the specified `length`.
+
+    :param x: the array to be sliced
+    :param start: the starting index
+    :param length: the length of the slice
+
     >>> df = spark.createDataFrame([([1, 2, 3],), ([4, 5],)], ['x'])
     >>> df.select(slice(df.x, 2, 2).alias("sliced")).collect()
     [Row(sliced=[2, 3]), Row(sliced=[5])]

sql/core/src/main/scala/org/apache/spark/sql/functions.scala

@@ -3265,6 +3265,11 @@ object functions {
   /**
    * Returns an array containing all the elements in `x` from index `start` (or starting from the
    * end if `start` is negative) with the specified `length`.
+   *
+   * @param x the array column to be sliced
+   * @param start the starting index
+   * @param length the length of the slice
+   *
    * @group collection_funcs
    * @since 2.4.0
    */