* doc: en translation for ram and cache
* doc: update currency from yuan to dollars
* doc: update EOF character
* doc: remove the redundant EOS character
* doc: remove redundant space character and polish several translations
* doc: polish translations
* doc: remove unnecessary 'the' and update translations
* Update ram_and_cache.md
* Update ram_and_cache.md
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Co-authored-by: Yudong Jin <krahets@163.com>