According to the phpDesigner online documentation you can use Regular Expressions in search and replace.
Please excuse the length of the following explanation. Doing it will be a lot simpler than reading the description.
Providing you have each list item on a single line of its own you can replace the start of line ( RegExp's ^ ) with <li> and the end of line ( RegExp's $ ) with </li>
Put Search and Replace into Regular Expression mode.
Method A: If your file contains only the items for your list then do a global replace of ^ with <li> and then another global replace of $ with </li>
Method B: If your file contains other items as well as your list items, place your insertion point before the start of your list, then replace ^ with <li> for each item of your list, then repeat replacing $ with </li> for each item of your list.
Method C: If you have a very long list in a file that contains other items, select the list, cut it from the file, past it into a temporary empty file, use Method A on your list, select the whole list, cut it from the temporary file, paste it back into your original file.
Please excuse the length of the following explanation. Doing it will be a lot simpler than reading the description.
Providing you have each list item on a single line of its own you can replace the start of line ( RegExp's ^ ) with <li> and the end of line ( RegExp's $ ) with </li>
Put Search and Replace into Regular Expression mode.
Method A: If your file contains only the items for your list then do a global replace of ^ with <li> and then another global replace of $ with </li>
Method B: If your file contains other items as well as your list items, place your insertion point before the start of your list, then replace ^ with <li> for each item of your list, then repeat replacing $ with </li> for each item of your list.
Method C: If you have a very long list in a file that contains other items, select the list, cut it from the file, past it into a temporary empty file, use Method A on your list, select the whole list, cut it from the temporary file, paste it back into your original file.