Content overview in search page don't work correctly for some languages.

[tohort]

I'm reporting a bug in search page.

I use japanese in django-wiki, but I found that content overview in search page is not work correctly especially in case using html tags in the content.

I realized that get_content_snippet() in wiki-tags.py is optimized only for the language using space between words, but Japanese don't use space between words.

I would like to propose the following in spite of current get_content_snippet()

@register.filter
def search_result_format(content, keyword, max_letters=300):

    content = striptags(content)
    content =re.sub(r'\r\n', ' ', content)
    content =re.sub(r'\n', ' ', content)
    keyword=re.escape(keyword)

    result=re.search(keyword, content, re.IGNORECASE)

    startposition=result.start()-int(max_letters/2)
    if startposition<0: startposition=0

    endposition=startposition+max_letters
    if endposition>len(content): endposition=len(content)

    result_content=content[startposition:endposition]

    if startposition>0:        
        #for the languages using space between words
        spase_position=result_content.find(" ")
        if spase_position >=0 and spase_position < 15: 
            result_content=result_content[spase_position:]

        result_content="...."+result_content

    if endposition<len(content):
        #for the languages using space between words
        spase_position=result_content.rfind(" ")
        if spase_position >=0 and len(result_content)-spase_position < 15: 
            result_content=result_content[:spase_position]

        result_content=result_content+"...."

    #html markup
    result_content=re.sub(r'('+keyword+')',r'<strong style="background:#ddd">\1</strong>',result_content ,flags=re.IGNORECASE)
    
    return result_content