docs: fixed typos (#4912)

Author: ricmoo

src.ts/providers/formatting.ts

@@ -52,7 +52,7 @@ export interface BlockParams {
 
     /**
      *  For proof-of-work networks, the difficulty target is used to
-     *  adjust the difficulty in mining to ensure a expected block rate.
+     *  adjust the difficulty in mining to ensure an expected block rate.
      */
     difficulty: bigint;
 

src.ts/utils/fixednumber.ts

@@ -212,7 +212,7 @@ function toString(val: bigint, decimals: number) {
  *  If operations are performed that cause a value to become too small
  *  (close to zero), the value loses precison and is said to //underflow//.
  *
- *  For example, an value with 1 decimal place may store a number as small
+ *  For example, a value with 1 decimal place may store a number as small
  *  as ``0.1``, but the value of ``0.1 / 2`` is ``0.05``, which cannot fit
  *  into 1 decimal place, so underflow occurs which means precision is lost
  *  and the value becomes ``0``.