Minor improvements to docs

Author: winderica

crates/fs/src/lib.rs

@@ -22,6 +22,7 @@
 //!     - Proof verification: [`FoldingSchemeVerifier`]
 //! - `circuits/`: In-circuit (partial / full) gadgets, mainly for verification.
 //! - `instances/`: Instance types.
+//! - `keys/`: Key types.
 //! - `witnesses/`: Witness types.
 
 pub mod definitions;

crates/primitives/src/circuits/mod.rs

@@ -96,7 +96,7 @@ pub trait FCircuit {
     ///
     /// ### Tips
     ///
-    /// - Since this method uses `self`, the implementation store some (fixed)
+    /// - Since this method uses `self`, the implementation can store some fixed
     ///   info that is shared across all steps inside `self`.
     /// - Variables in the implementation should be allocated as witnesses (not
     ///   public inputs) in the implementation.