Typo fix in builtins.rst & types.rst (#1792)

Signed-off-by: Pratyksh <pratykshgupta9999@gmail.com>

docs/language/builtins.rst

@@ -142,7 +142,7 @@ Polkadot
 ~~~~~~~~
 
 uint128 ``block.minimum_deposit``
-    The minimum amonut needed to create a contract. This does not include
+    The minimum amount needed to create a contract. This does not include
     storage rent.
 
 Ethereum

docs/language/types.rst

@@ -416,7 +416,7 @@ named arguments and returns.
   keccak256 calculation.
 
 If you access a non-existing field on a mapping, all the fields will read as zero. It
-is common practise to have a boolean field called ``exists``. Since mappings are not iterable,
+is common practice to have a boolean field called ``exists``. Since mappings are not iterable,
 it is not possible to ``delete`` an entire mapping itself, but individual mapping entries can be deleted.
 
 .. note::