doc: document unspecified behavior for buf.write* methods
Pull Request check-list
-
Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?
Affected core subsystem(s)
doc/api/buffer.markdown
Description of change
Per https://github.com/nodejs/node/issues/1161, when the buf.write*() methods are given anything other than what they expect, indicate that the behavior is unspecified.