Ignore the output from DocC for publication.

amartini51 · amartini51 · commit e31d520d37ac · 2023-01-24T15:15:27.000-08:00
This directory is created by the bin/publish-book script.
diff --git a/.gitignore b/.gitignore
@@ -4,3 +4,4 @@
 /.build
 /Package.resolved
 /TSPL.docc/header.html
+/swift-book
