Fixed broken links.

Author: DariuszDepta

docs/core/standard-library/cryptography/cryptography.md

@@ -71,5 +71,5 @@ Keep in mind that, thanks to Wasm being our execution environment, contract exec
 In most cases the perceived need to move hashing into a host function is premature optimization and
 not actually needed.
 
-[check this page]: ../../architecture/gas
+[check this page]: ../../architecture/gas.md
 [source code]: https://github.com/CosmWasm/cosmwasm/blob/main/packages/vm/src/environment.rs#L62-L101

docs/core/standard-library/math/math.md

@@ -16,5 +16,5 @@ only shows the unsigned case but the signed types work the same way.
 `::to_*` are functions on the source type and `::new`/`::from_*` are functions on the destination
 type.
 
-[integers]: ./integers
-[decimals]: ./decimals
+[integers]: ./integers.md
+[decimals]: ./decimals.md