Update occurrence parameter description in regexp-replace (#10230)

Author: OleksiiKovalov

docs/t-sql/functions/regexp-replace-transact-sql.md

@@ -82,7 +82,7 @@ The numbering is 1-based, meaning the first character in the expression is `1` a
 
 #### *occurrence*
 
-An expression (positive integer) that specifies which occurrence of the pattern expression within the source string to be searched or replaced. Default is `1`. Searches at the first character of the *string_expression*. For a positive integer `n`, it searches for the `nth` occurrence beginning with the first character following the first occurrence of the *pattern_expression*, and so forth.
+An expression (positive integer) that specifies which occurrence of the pattern expression in the source string should be searched or replaced. The default value is `0`, which means all occurrences of the *pattern_expression* are replaced. For a positive integer `n`, it searches *string_expression* for the `n`th occurrence, continuing the search from the character immediately following each previous match.
 
 #### *flags*