Python: Rename WeakCrypto to WeakCryptoKey

Since WeakCrypto always makes me think that it's about all weak crypto (like
using MD5, or completely broken ciphers such as ARC4 ro DES) and not just about
weak key generation.

python/change-notes/2021-02-02-port-weak-crypto-key-query.md

@@ -1,2 +1,3 @@
 lgtm,codescanning
 * Ported _Use of weak cryptographic key_ (`py/weak-crypto-key`) query to use new type-tracking approach instead of points-to. This might result in some difference in results being found, but overall this should result in a more robust and accurate analysis.
+* Renamed the query file for _Use of weak cryptographic key_ (`py/weak-crypto-key`) from `WeakCrypto.ql` to `WeakCryptoKey.ql` (in the `python/ql/src/Security/CWE-326/` folder), which could impact custom query suites that include/exclude this query by using it's path.

python/ql/test/query-tests/Security/CWE-326/WeakCrypto.qlref

@@ -1 +0,0 @@
-Security/CWE-326/WeakCrypto.ql

python/ql/test/query-tests/Security/CWE-326/WeakCryptoKey.qlref

@@ -0,0 +1 @@
+Security/CWE-326/WeakCryptoKey.ql