Have fix bit typo README.md (#364)

Writing source documentation section

README.md

@@ -243,7 +243,7 @@ There should be json between `<literalinclude>` open & close tags.
 ### Writing source documentation
 
 Arguments of a function/class/method should be defined with the `Args:` (or `Arguments:` or `Parameters:`) prefix, followed by a line return and
-an indentation. The argument should be followed by its type, with its shape if it is a tensor, a colon and its
+an indentation. The argument should be followed by its type, with its shape if it is a tensor, a colon, and its
 description:
 
 ```
@@ -252,7 +252,7 @@ description:
 ```
 
 If the description is too long to fit in one line, another indentation is necessary before writing the description
-after th argument.
+after the argument.
 
 Here's an example showcasing everything so far: