Add more redirects

[fredemmott]

Done

• [x] 15 /hack/types/casting
• [x] 14 /hack/other-features/trait-and-interface-requirements
• [x] 14 /hack/lambdas/
• [x] 13 /hack/operators/lambda
• [x] 13 /hack/attributes/special
• [x] 12 /hack/operators/null-safe
• [x] 12 /hack/operators/introduction
• [x] 12 /hack/lambdas/introduction
• [x] 11 /hack/typechecker/modes
• [x] 11 /hack/lambdas/creation-story
• [x] 10 /hack/types/annotations
• [x] 9 /hack/tuples/use-cases
• [x] 9 /hack/operators/pipe-operator
• [x] 9 /hack/callables/special-functions
• [x] 8 /hack/types/summary-table
• [x] 8 /hack/types/inference
• [x] 8 /hack/type-aliases/transparent
• [x] 8 /hack/tuples/introduction
• [x] 8 /hack/other-features/placeholder-variable
• [x] 8 /hack/lambdas/examples
• [x] 7 /hack/typechecker/setup
• [x] 7 /hack/typechecker/running
• [x] 7 /hack/type-constants/introduction
• [x] 7 /hack/type-constants/examples
• [x] 7 /hack/type-constants/constraints
• [x] 7 /hack/type-aliases/opaque
• [x] 7 /hack/lambdas/design
• [x] 7 /hack/attributes/syntax
• [x] 6 /hack/type-aliases/examples
• [x] 6 /hack/other-features/variadic-functions
• [x] 6 /hack/other-features/autoloading
• [x] 3 /hack/type-aliases/introduction
• [x] 2 /hack/type-constants/
• [x] 2 /hack/tuples/

Missing content

• [ ] 8 /hack/disposables/async-disposables
• [ ] 8 /hack/disposables/factory-functions
• [ ] 8 /hack/attributes/type-checking
• [ ] 7 /hack/types/advanced-rules
• [ ] 6 /hack/types/runtime
• [ ] 8 /hack/typechecker/options
• [ ] 6 /hack/typechecker/install
• [ ] 6 /hack/typechecker/special
• [ ] 7 /hack/operators/XHP-attribute-access

Intentionally removed

• [ ] 9 /hack/unsupported/intrinsics
• [ ] 8 /hack/unsupported/references
• [ ] 7 /hack/tuples/relationship-to-arrays
• [ ] 7 /hack/unsupported/top-level
• [ ] 7 /hack/unsupported/others
• [ ] 6 /hack/unsupported/html

No suitable replacement

• [ ] 2 /hack/FAQ/
• [ ] 8 /hack/FAQ/faq

What is this?

• [ ] 5 /hack/reference/trait
• [ ] 5 /hack/reference/function
• [ ] 5 /hack/reference/class
• [ ] 4 /hack/reference/interface