Add documentation to StoreId type

lib/core/libimagstore/src/storeid.rs

@@ -38,6 +38,10 @@ use iter::get::StoreGetIterator;
 use iter::retrieve::StoreRetrieveIterator;
 
 /// The Index into the Store
+///
+/// A StoreId object is a unique identifier for one entry in the store which might be present or
+/// not.
+///
 #[derive(Debug, Clone, Hash, Eq, PartialOrd, Ord)]
 pub struct StoreId {
     base: Option<PathBuf>,
@@ -104,6 +108,11 @@ impl StoreId {
         Ok(base)
     }
 
+    /// Check whether the StoreId exists (as in whether the file exists)
+    ///
+    /// # Warning
+    ///
+    /// Should be considered deprecated
     pub fn exists(&self) -> Result<bool> {
         self.clone().into_pathbuf().map(|pb| pb.exists())
     }