PHP 8.1 Deprecated function: preg_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated in apachesolr_autocomplete_suggest_word_completion()

Problem/Motivation

Deprecated function: preg_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated in apachesolr_autocomplete_suggest_word_completion() (line 250 of /apachesolr_autocomplete/apachesolr_autocomplete.module).

Steps to reproduce

1. Search for ' *' used autocomplete.
2. Go to dblog
3. Locate deprecated function

Proposed resolution

so I used Elvis operator ( ?: ) to bypass null value