docs: improve writing and formatting
docs: fix typos in NatSpec
feat: add "_calculateStreamedAmount" in linear contract
feat: add "isCanceled", "isDepleted", "isStream" fields in in stream structs
perf: dedup `_withdrawableAmountOf`
refactor: alphabetical ordering
refactor: delete "isSettled"
refactor: delete "status" field in stream structs
refactor: explicit null checks
refactor: improve error names
refactor: move withdraw amount check in each streaming contract
refactor: rename "isActive" to "isWarm"
refactor: rename "getStatus" to "statusOf"
test: add "has been canceled" branch in state trees
test: add a new fuzz test for "cancel"
test: add a new fuzz test for "withdrawMax"
test: add constant "MARCH_1_2023"
test: allow depleted streams in dynamic fuzz tests
test: allow depleted streams in fork tests
test: delete unused imports
test: de-dup "streamedAmountOf" tests
test: de-dup "withdrawableAmountOf" tests
test: expect transfer calls in all "withdraw" fuzz tests
test: improve function and variable names
test: improve nesting structures in state trees
test: improve wording in comments
test: improve wording in state trees
test: remove status check in "createWithDeltas" tests
test: remove superfluous comments
test: rename "whenStreamActive" to "whenStatusStreaming"
test: test post-withdraw status in fork tests
test: update tests in light of new contract API
test: use keywords for time calculations
test: various enhancements

Rename `WithdrawAmountGreaterThanWithdrawableAmount` to `Overdraw`

Close #458

docs: improve writing
refactor: delete "Status.NULL"
refactor: rename "isNotNull" to "notNull"
refactor: rename "isWarm" to "warm"
refactor: revert on null streams in "statusOf"
test: add tests for "isStream"
test: fix pre-conditions in "LockupHandler"
test: improve function names
test: refactor modifiers in "LockupHandler"
test: update tests for "statusOf"

refactor: refactor "warm" into "notCold"
refactor: rename "StreamNotWarm" error to "StreamCold"
test: add tests for "isCold" and "isWarm"
test: delete superfluous tests
test: improve names of state trees
test: improve orders of operations in tests

Refactor `lockup/shared` to `lockup`
Refactor `lockup/linear` to `lockup-linear`
Refactor `lockup/dynamic` to `lockup-dynamic`

test: improve writing in comments
test: improve writing in function and variable names
test: improve state trees

docs: improve writing in comments
test: remove "whenCaller" tests in "withdrawMultiple"
test: fix, improve, and simplify "withdrawMultiple" tests
test: fix and improve "withdraw" tests
test: improve naming in state trees

Rename "WithdrawSenderUnauthorized" to "InvalidSenderWithdrawal"

test: run "cancelMultiple" fuzz tests

Closes #463

test: change order of streams in "withdrawMultiple"
test: use named args in expect calls helpers

See #461 (comment)

test: alphabetical ordering
test: add "deployBaseTestContracts"
test: add "labelBaseTestContracts"
test: add "SEGMENT_COUNT"
test: bound instead of assume in "createWithRange" test
test: deploy base contract via bespoke helper function
test: fix variable names
test: improve wording in comments
test: label base contracts via bespoke helper function
test: delete "DEFAULT_ASSET"
test: delete unneeded "Calculations" inheritance
test: deploy and label base test contracts in "Base_Test.setUp"
test: hard code bound values in invariant tests
test: inherit from "Constants" in "Base_Test"
test: improve wording in comments
test: replace local max uint256 constant with PRBTest constant
test: rename "dai" to "usdc"

perf: mark "isCold" and "isWarm" as "external"
refactor: change declaration place of "segmentCount"
test: add "assertNotEq" for "Lockup.Status"
test: group status invariant tests
test: improve wording

test: add all shared modifiers in "streamedAmountOf"
test: add all shared modifiers in "withdrawableAmountOf"
test: alphabetical ordering

test: add private "params" in shared tests
test: delete internal "defaultParams"
test: deploy and label directly in "Base_Test.setUp"
test: define "createDefaultStreamWithTotalAmount" in shared contract
text: expand "Defaults" with more default values
test: use direct values instead of loading them from default params
test: move statements around so make "vm.expectRevert" work
test: move "Users" in "test/utils/Types"
test: provide default create function params in "Defaults"
test: various refactors and improvements

docs: improve writing
test: test cold streams in "isCancelable"
test: fix mistaken comment in invariant tests

test: prank back to sender after setting protocol fee

docs: document numerical values for "Status" enum
perf: remove unneeded "streamId" variable
perf: remove unneeded "uin256()" casting
test: add missing error strings in assertions

docs: improve writing in comments
docs: remove superfluous comments

feat: add "_isDepleted" internal getter
refactor: delete "_checkParamsAndWithdraw" function
refactor: delete "StreamPending" error
test: refine "cancelMultiple" and "withdrawMultiple" tests
test: update state trees in light of new contract API

docs: improve writing in comments
feat: add "_wasCanceled" getter
refactor: check cold statuses directly in "renounce"
refactor: delete "notCold" modifier
refactor: emit specific statuses instead of "StreamCold"
test: update state trees in light of new contract API

docs: improve writing in comments
test: test "isDepleted" getter
test: test "wasCanceled" getter

refactor: delete unneeded modifier uses
refactor: merge "wasCanceled" with "_wasCanceled"
refactor: remove "onlySenderOrRecipient" modifier