Package identifier syntax

While developing a syntax highlighter for WIT, I discovered some sources of confusion (for me at least) regarding package identifiers.

The punctuation symbols in package identifiers (specifically : and .) clash visually with other uses of those same symbols. Examples:

export example:http-client // An export named `example` of type `http-client`
export example:http/client // An export named `client` from the package `example:http`
// The tricky part for me is that one symbol, half-way through a line,
// affects the meaning of what was declared _earlier_ in that line.
// This is awkward to implement in TextMate grammars (which are regex!).


// and:

use example:http/client@1.0.0-beta.nginx.{ request, response }

// It may look like we're "drilling into" some sort of `nginx` submodule
// of the `example:http/client@1.0.0-beta` package, but actually `nginx` is part of the
// semver 'prerelease' component. The actual package id here is: `example:http/client@1.0.0-beta.nginx`
// Moreover, the last period __is__ a "drilling into" period (the one before the curly brace)

One solution could be to enclose package identifiers in quotes like JS and Go do. That way it is immediately clear where the identifier starts and ends, even for developers not intimately familiar with Wit syntax.
Tangentially related; in the example below I've hoisted the interface selector (/client) out of the package name, so that package identifier strings are the same everywhere, regardless of where in the wit file they're used.

export example: http-client  // An export named `example` of type `http-client`
export "example:http".client // An export named `client` from the package `example:http`

// and:

use "example:http@1.0.0-beta.nginx".client.{ request, response }

Start by reading the package-identifier examples in the issue and reviewing the current WIT syntax and its treatment of colons, periods, selectors, and prerelease versions. A decision between the proposed alternatives, followed by corresponding specification changes and validation of the examples, would define done.