Fix erronerous links with extention contains dot

[MartyLake]

Directly use the wiki extension setting instead of removing last dot.

Reproduciton steps

Set wiki extension to .wiki.txt:

let g:vimwiki_list = [{
            \"path": $REDACTED."/Wiki",
            \"path_html": $REDACTED."/Wiki_html",
            \'template_path': $REDACTED."/Wiki_html_assets",
            \'template_default': 'default',
            \'template_ext': '.html',
            \'generated_links_caption': 1,
            \'auto_export': 1,
            \'auto_toc': 0,
            \'auto_diary_index': 1,
            \'auto_generate_links': 1,
            \'auto_generate_tags': 1,
            \'maxhi': 1,
            \'syntax': 'default',
            \'ext': '.wiki.txt',
            \'index': 'index',
            \'auto_tags': 1}]

Create a note with filename "2024-04-30.wiki.txt" Edit another wiki note, in insert mode [[ search for previous note to insert a link.

Before this patch

Link inserted [[2024-04-30.wiki|Content]] does not work

After this patch

Link inserted [[2024-04-30|Content]] works

[michal-h21]

Thanks!