doc: replace sane with reasonable
doc: replace sane with reasonable

Removing ableist language because we don't need to make the comparison
to people with mental health issues to get our point across.

PR-URL: https://github.com/nodejs/node/pull/3980
Reviewed-By: Evan Lucas <ad0310dc5270cefb6ee6879263270aed9b1e9982@me.com>
Reviewed-By: Michaël Zasso <dc852f7f42c586356f6be32b8780273088b3bded@gmail.com>
Reviewed-By: Colin Ihrig <838f779c91673db29b8572ea3f54d191d3878ae2@gmail.com>

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node