Add pronunciation tips for abbreviations

[daobrien]

Abbreviations often require the use of an indefinite article, and whether you choose "a" or "an" depends on pronunciation. Not all pronunciations are obvious. e.g., RHV, which used to be RHEV, is still pronounced as an acronym, REV, and hence requires "a" as the indefinite article.

I don't think anything special is required, just a note "pronounced REV" after the expansion and any tags:
RHV: Red Hat Virtualization @Virtualization (pronounced REV)

Open to suggestions. @ggainey ?

• RHV
• HMAC
• HOTP
• ACE
• RHV-M
• RHV-H
  There are plenty more that need help, and some that I don't even know. Feel free to help.

[daobrien]

Working on this syntax:

<abbreviation>: <expansion> [@tags] [(pron. <pronunciation>)] [URL]

e.g.

RHV: Red Hat Virtualization @Virtualization (pron. rĕv)

[daobrien]

This appears to work and is supported in the output.

<davido> !rhv
<acrobot> RHV: Red Hat Virtualization @RH, @virtualization (pron. rĕv)