pick formatting for const object and apply it consistently

[zygoloid]

The definition of the term const object (and friends) does not use teletype font for the "const", and nor do nearby uses of the term. However, other uses of this term in the standard do use a teletype font. We should pick one or the other and do it consistently. I'm not sure we can use italic teletype, so perhaps that forces us to use the non-teletype font everywhere.

(This same thing happens in a bunch of other places, for instance the terms 'constexpr constructor' and 'return statement'.)

[cpplearner]

Actually, italic teletype is already used in [conv]p4, the definition of "contextually converted to bool".

[zygoloid]

Hmm, it looks like LaTeX used bold italic monospace, not some kind of teletype font, there. Note the shapes of the 'b' and 'l' characters and the generally awful appearance...

[jensmaurer]

Editorial meeting consensus: We define the term-of-art "const object" etc, so no \tcode is used. See also #106 and related issues.

Leave [conv]p4, the definition of "contextually converted to bool", as-is.