API: coarse-grained checker queries for whole-program extraction tools - #65351

…cker queries for traversal tools

Tools that walk a whole program (binding generators, documentation
generators, API extractors) ask the checker, for every member of every
type, for its documentation and its type, and skip most members after
looking at them. Over the synchronous API that is several round trips per
member, and the server materializes a type for members the caller then
discards.

getSymbolDocumentations returns the JSDoc tags and documentation comment of
many symbols in one request, element for element equal to getJsDocTags and
getDocumentationComment.

getMembersOfType returns the properties of a type that pass a filter, each
with its documentation, the symbol of the type declaring it and, on request,
its declared type. The filter is a set of neutral predicates (visibility,
member kind, excluded JSDoc tags, an excluded name pattern, which declaring
types to take members from) that the caller combines to describe the members
it will render; a tool's own policy stays in the tool. Members come back in
getPropertiesOfType order with the same symbol and type handles.

The Go tests include a differential fixture: a class hierarchy with
overrides, overloads, accessors, every visibility including an ECMAScript
private name, a parameter property and excluded members, checked member by
member against what the fine-grained path (getPropertiesOfType +
getTypeOfSymbolAtLocation + getJsDocTags + getDocumentationComment) reports.
The client tests cover the two methods through the API and in the
generator batching parity suite.

Refs: microsoft#65051

…er than their first declaration

Review of the first version found six gaps, all in how a member's metadata
was derived from its first declaration:

- Members without a declaration (tuple elements, a tuple's `length`) were
  dropped even with no filter, so the result diverged from
  getPropertiesOfType. They are kept, classified from their symbol flags,
  have no owner, and their declared type comes from getTypeOfSymbol, which
  needs no location; the declared type of every member is now obtained that
  way.
- Visibility is read with GetDeclarationModifierFlagsFromSymbol, so a
  getter/setter pair is classified by the getter whatever the declaration
  order, and a synthetic union or intersection member by its constituents.
  ECMAScript private names still count as private.
- isMethod is derived from the same classification as the `method` kind, so
  the synthetic member of `{ m(): number } | { m(): string }`, which carries
  no method flag, is a method and gets no declared type.
- Auto-accessors (`accessor x = 0`) are accessors, like explicit getters and
  setters.
- excludeNamePattern distinguishes absent from empty: a pattern that is
  passed is always compiled, and the empty pattern matches every member.
- MemberFilterInput accepts an explicit `undefined` for every optional field,
  nested ones included, under exactOptionalPropertyTypes.

Each gap has a test that failed before the change.

Refs: microsoft#65351