Running the plugin using Xcode 13 produces error 'variable binding in a condition requires an initializer'

[SRowley90]

When trying to generate Documentation Using Xcode 13 from the main branch, 2 errors occur with the same message variable binding in a condition requires an initializer both in the Snippet Parser class of the Package. This does not occur when using the package with Xcode 14 (beta at the time of writing this)

Checklist

• If possible, I've reproduced the issue using the main branch of this package.
• This issue hasn't been addressed in an existing GitHub issue.

Expected behavior

Documentation to be generated when using Xcode 13

Actual behavior

Error (variable binding in a condition requires an initializer) is thrown.

Steps to Reproduce

Using the following command against the main branch of this repository causes the issue, it does not happen when using Xcode 14 or when pointing to the older 1.0.0 Release (but obviously this is old).

swift package --allow-writing-to-directory ./public generate-documentation --target JLRAnalytics --disable-indexing --output-path ./public --transform-for-static-hosting --hosting-base-path 'jlranalytics'

Swift-DocC Plugin Version Information

Swift-DocC plugin version: main
Swift Compiler version: swift-driver version: 1.45.2 Apple Swift version 5.6.1 (swiftlang-5.6.0.323.66 clang-1316.0.20.12) Target: x86_64-apple-macosx12.0