Update docs for appveyor badge.

diff --git a/src/doc/manifest.md b/src/doc/manifest.md
index 4a72712d2231ca123ded2c7fea02a8f69f7696b8..2b22150576dc0361f7f3ca5be30360d0170016af 100644 (file)
--- a/src/doc/manifest.md
+++ b/src/doc/manifest.md
@@ -192,7 +192,8 @@ license-file = "..."
 # Appveyor: `repository` is required. `branch` is optional; default is `master`
 # `service` is optional; valid values are `github` (default), `bitbucket`, and
 # `gitlab`; `id` is optional; you can specify the appveyor project id if you 
-# want to use that instead.
+# want to use that instead. `project_name` is optional; use when the repository
+# name differs from the appveyor project name.
 appveyor = { repository = "...", branch = "master", service = "github" }
 
 # Circle CI: `repository` is required. `branch` is optional; default is `master`