Fix typos (#290)

* fix typo

* fix typo

* Fix typo

src/gadgets/ecc.rs

@@ -193,7 +193,7 @@ where
   }
 
   /// Adds other point to this point and returns the result. Assumes that the two points are
-  /// different and that both `other.is_infinity` and `this.is_infinty` are bits
+  /// different and that both `other.is_infinity` and `this.is_infinity` are bits
   pub fn add_internal<CS: ConstraintSystem<E::Base>>(
     &self,
     mut cs: CS,

src/provider/traits.rs

@@ -92,7 +92,7 @@ pub trait DlogGroup:
   /// Returns the generator of the group
   fn gen() -> Self;
 
-  /// Returns the affine coordinates (x, y, infinty) for the point
+  /// Returns the affine coordinates (x, y, infinity) for the point
   fn to_coordinates(&self) -> (<Self as Group>::Base, <Self as Group>::Base, bool);
 }
 

src/traits/commitment.rs

@@ -54,7 +54,7 @@ pub trait CommitmentTrait<E: Engine>:
   fn decompress(c: &Self::CompressedCommitment) -> Result<Self, NovaError>;
 }
 
-/// A trait that helps determine the lenght of a structure.
+/// A trait that helps determine the length of a structure.
 /// Note this does not impose any memory representation contraints on the structure.
 pub trait Len {
   /// Returns the length of the structure.