Improve documentation

[miparnisari]

Issue #, if available: #903

Description of changes:

• Fixes typos
• Adds instructions on how to setup development environment

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[miparnisari]

@kddejong Are there any instructions on how to debug tests? I wasn't able to get a configuration for this on VS Code.

[kddejong]

Let me try it out again.... I'm pretty sure I got it working at one point.

[miparnisari]

I was able to run & debug the tests on PyCharm by right-clicking the tox.ini file and clicking Run & Debug

[PatMyron]

At least one of these properties must be specified:
https://github.com/aws-cloudformation/cfn-python-lint/blob/b788cc9bd3d49ed20d5f2e58602755a0ef37f52c/src/cfnlint/data/AdditionalSpecs/AtLeastOne.json#L20-L25

Only one of these properties may be specified:
https://github.com/aws-cloudformation/cfn-python-lint/blob/b788cc9bd3d49ed20d5f2e58602755a0ef37f52c/src/cfnlint/data/AdditionalSpecs/OnlyOne.json#L79-L84

If this property (SnapshotIdentifier) is specified, these properties must be excluded:
https://github.com/aws-cloudformation/cfn-python-lint/blob/b788cc9bd3d49ed20d5f2e58602755a0ef37f52c/src/cfnlint/data/AdditionalSpecs/Exclusive.json#L102-L107

If this property (VpcId) is specified, these properties must be included:
https://github.com/aws-cloudformation/cfn-python-lint/blob/b788cc9bd3d49ed20d5f2e58602755a0ef37f52c/src/cfnlint/data/AdditionalSpecs/Inclusive.json#L48-L52

---

Allowed patterns:
https://github.com/aws-cloudformation/cfn-python-lint/blob/a46773c752247c51effef415bd3462eaec10ab0b/src/cfnlint/data/ExtendedSpecs/all/03_value_types.json#L33-L36

Allowed values:
https://github.com/aws-cloudformation/cfn-python-lint/blob/6cce9222c89056f1546f6fee068ce6dc9dfa394e/src/cfnlint/data/ExtendedSpecs/all/03_value_types/aws_codebuild.json#L2-L11

List size constraints:
https://github.com/aws-cloudformation/cfn-python-lint/blob/6cce9222c89056f1546f6fee068ce6dc9dfa394e/src/cfnlint/data/ExtendedSpecs/all/03_value_types/aws_iam.json#L71-L78

Number size constraints:
https://github.com/aws-cloudformation/cfn-python-lint/blob/df8d065380e49e53dad9513dab41c2438e105f43/src/cfnlint/data/ExtendedSpecs/all/03_value_types/aws_sqs.json#L17-L24

String size constraints:
https://github.com/aws-cloudformation/cfn-python-lint/blob/67fc5bb210b020e3226261f966a01726d574475d/src/cfnlint/data/ExtendedSpecs/all/03_value_types/aws_logs.json#L2-L9

---

There should be no functional difference, but src/cfnlint/data/ExtendedSpecs/all/03_value_types and src/cfnlint/data/ExtendedSpecs/all/04_property_values are more organized than src/cfnlint/data/ExtendedSpecs/all/03_value_types.json and src/cfnlint/data/ExtendedSpecs/all/04_property_values.json, so they should be preferred locations for new constraints

---

After editing these files, the rest of the necessary changes should be auto-generatable by running:

cfn-python-lint $ pip3 install -e . --user
cfn-python-lint $ cfn-lint --update-specs