Optimize the language detection logic to enhance content formatting.  This
change addresses issues with long word segmentation. Language detection now uses a
threshold to determine the language of a text based on the proportion of English characters.
Formatting rules for content have been updated to consider a list of languages (initially
including Chinese, Japanese, and Korean) where no space is added between content segments
for inline equations and text spans, improving the handling of Asian languages.

The impact of these changes includes improved accuracy in language detection, better
segmentation of long words, and more appropriate spacing in content formatting for multiple
languages.