Use bolding only for warnings?

As discussed at #297 (e.g. this comment by @ericonr), i think it would be good to draw readers' attention to warnings via bolding. However, to ensure a consistent meaning for bolding, i think it should perhaps only be used in such cases, rather than to e.g. introduce terms, as in #177, where emphasis via *term* could be used instead.

(However, i don't think this issue should be considered a blocker for #177.)

まず issue #297、@ericonr によるリンク先のコメント、issue #177 を確認し、ドキュメントにおける太字と強調の提案された意味を理解します。影響を受けるドキュメントの使用箇所を特定し、警告のみを出す一貫した方針に合意したうえで、対象範囲が確定したら関連する Markdown の内容を更新します。