feat: static variable analysis (#770)

* feat: static variable analysis

* Accept any iterable from `children`, `arguments`, etc.

* Test analysis of standard tags

* Use `TagToken.tokenizer` instead of creating a new one

* Test analysis of netsted tags

* Group variables by their root value

* Test analysis of nested globals and locals

* Analyze included and rendered templates WIP

* Use existing tokenizer when constructing `Hash`

* Improve test coverage

* Analyze variables from `layout` and `block` tags

* Test analysis of Jekyll style includes

* Handle variables that start with a nested variable

* Async analysis

* Test non-standard tag end to end

* Implement convenience analysis methods on the `Liquid` class

* More analysis convenience methods

* Accept string or template array

* Draft static analysis docs

* Deduplicate variables names

* Fix isolated scope global variable map

* Coerce variables to strings instead of extending String

* Private map instead of extending Map

* Fix e2e test

* Tentatively implement analysis of aliased variables

* Fix nested variable segments array

* Update docs sidebar

src/index.ts

@@ -6,9 +6,9 @@ export { Drop } from './drop'
 export { Emitter } from './emitters'
 export { defaultOperators, Operators, evalToken, evalQuotedToken, Expression, isFalsy, isTruthy } from './render'
 export { Context, Scope } from './context'
-export { Value, Hash, Template, FilterImplOptions, Tag, Filter, Output } from './template'
+export { Value, Hash, Template, FilterImplOptions, Tag, Filter, Output, Variable, VariableLocation, VariableSegments, Variables, StaticAnalysis, StaticAnalysisOptions, analyze, analyzeSync, Arguments, PartialScope } from './template'
 export { Token, TopLevelToken, TagToken, ValueToken } from './tokens'
-export { TokenKind, Tokenizer, ParseStream } from './parser'
+export { TokenKind, Tokenizer, ParseStream, Parser } from './parser'
 export { filters } from './filters'
 export * from './tags'
 export { defaultOptions, LiquidOptions } from './liquid-options'