rust: kernel: add srctree-relative doclinks

BugLink: https://bugs.launchpad.net/bugs/2101915

Convert existing references to C header files to make use of
Commit bc2e7d5c29 ("rust: support `srctree`-relative links").

Signed-off-by: Valentin Obst <kernel@valentinobst.de>
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240131-doc-fixes-v3-v3-4-0c8af94ed7de@valentinobst.de
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
(cherry picked from commit ed8596532a667e1a25ef0293acbb19078b94f686)
[koichiroden: pulled in a minor prerequisite commit]
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

rust/kernel/lib.rs

@@ -77,7 +77,7 @@ pub trait Module: Sized + Sync + Send {
 
 /// Equivalent to `THIS_MODULE` in the C API.
 ///
-/// C header: `include/linux/export.h`
+/// C header: [`include/linux/export.h`](srctree/include/linux/export.h)
 pub struct ThisModule(*mut bindings::module);
 
 // SAFETY: `THIS_MODULE` may be used from all threads within a module.

rust/kernel/sync/condvar.rs

@@ -77,6 +77,8 @@ pub struct CondVar {
 
     /// A condvar needs to be pinned because it contains a [`struct list_head`] that is
     /// self-referential, so it cannot be safely moved once it is initialised.
+    ///
+    /// [`struct list_head`]: srctree/include/linux/types.h
     #[pin]
     _pin: PhantomPinned,
 }