Update README.md (#3340)

updated the punctuation of the counter README.md file

Signed-off-by: Arinaitwe Allan <133093725+arinaitweallan@users.noreply.github.com>

examples/counter/README.md

@@ -8,7 +8,7 @@ unsigned integer that can be increased by the `increment` operation.
 It is a very basic Linera application, which is initialized by a `u64` which can be incremented
 by a `u64`.
 
-For example if the contract was initialized with 1, querying the contract would give us 1. Now if we want to
+For example, if the contract was initialized with 1, querying the contract would give us 1. Now if we want to
 `increment` it by 3, we will have to perform an operation with the parameter being 3. Now querying the
 application would give us 4 (1+3 = 4).