B324: hashlib_new not included in help docs

[ericwb]

Describe the bug
The doc for B324 hashlib_new is not included as part of:
https://bandit.readthedocs.io/en/latest/plugins/index.html

This may be because 3xx is for blacklist, yet this is a plugin.

To Reproduce
Steps to reproduce the behavior:

1. Go tohttps://bandit.readthedocs.io/en/latest/plugins/index.html
2. Notice B324 is missing in the list of plugins

Note, it is not listed here either:
https://bandit.readthedocs.io/en/latest/blacklists/blacklist_calls.html

Expected behavior
Output of command bandit -h shows

	B324	hashlib_new_insecure_functions

But it's not documented in the help docs

Bandit version

bandit 1.6.3
  python version = 3.6.7 (default, Nov 12 2018, 13:31:42) [GCC 4.2.1 Compatible Apple LLVM 10.0.0 (clang-1000.11.45.5)]

Additional context
Add any other context about the problem here.

[smontanaro]

I assume this is why when I get an error referencing hashlib like this:

Issue: [B324:hashlib] Use of weak MD4, MD5, or SHA1 hash for security. Consider usedforsecurity=False
Severity: High Confidence: High
CWE: CWE-327 (https://cwe.mitre.org/data/definitions/327.html)
Location: ./scripts/cull-dups.py:24:25
More Info: https://bandit.readthedocs.io/en/1.7.4/plugins/b324_hashlib.html

the More Info URL doesn't exist. I just installed bandit, so 1.7.4 is probably the latest release, but just in case, I tried this URL too:

https://bandit.readthedocs.io/en/latest/plugins/b324_hashlib.html

but it also 404s.

[manuel-belvo]

This issue is still present since the output gives:

>> Issue: [B324:hashlib] Use of weak MD4, MD5, or SHA1 hash for security. Consider usedforsecurity=False
   Severity: High   Confidence: High
   CWE: CWE-327 (https://cwe.mitre.org/data/definitions/327.html)
   Location: src/a.py
   More Info: https://bandit.readthedocs.io/en/1.7.4/plugins/b324_hashlib.html