[librsvg: 1/9] Toplevel docs for the c_api module

[Federico Mena Quintero <federico src gnome org>]

commit 5053cbca124d8708aabe4047f2a906c7e94f74a7
Author: Federico Mena Quintero <federico gnome org>
Date:   Wed May 26 18:47:16 2021 -0500

    Toplevel docs for the c_api module

 src/c_api/mod.rs | 5 +++++
 1 file changed, 5 insertions(+)
---
diff --git a/src/c_api/mod.rs b/src/c_api/mod.rs
index fae73f75..b46e16cd 100644
--- a/src/c_api/mod.rs
+++ b/src/c_api/mod.rs
@@ -1,3 +1,8 @@
+//! C API for librsvg, based on GObject.
+//!
+//! The main API is in the [`handle`](handle/index.html) module.  The other modules
+//! have utility functions and the legacy [pixbuf-based API](pixbuf_utils/index.html).
+
 #![allow(clippy::missing_safety_doc)]
 
 #[rustfmt::skip]