textDocument/{declaration,definition,typeDefinition} return either LocationLink[] or Location[]
Add an initialization option client.linkSupport . When it is false, ccls will return Location[] disregarding client's linkSupport.
`struct LocationLink` does not include originSelectionRange as it is wasteful.
* WorkingFiles::files : vector -> unordered_map
* Add timestamp to WorkingFile
* Rename "comp-preload" thread to "preamble"
* Rename CompletionManager to SemaManager as it is used by "diag" "comp" "preamble"
* Rename clang_complete.* to sema_manager.*
* Merge SemaManager::{preloads,sessions}
* Add initialization option session.maxNum
* In DiagnosticMain, if an included file was modified, cancel the DiagTask and create a PreambleTask instead. The task sets `from_diag` so as to trigger immediate DiagTask after the preamble is built.
Delete method.{cc,h}
Rename $ccls/setSkippedRanges to $ccls/publishSkippedRanges
Rename $ccls/publishSemanticHighlighting to $ccls/publishSemanticHighlight; stableId -> id
Move using below #include to make preamble happy
textDocument/references: if no references, first line or last line => list where this file is included
malloc_trim() only if files have been indexed in last cycle
Intern: use CachedHashStringRef
Before, QueryFile::Def::{all_symbols,outline} were built by indexers.
Now, {symbol,outline}2refcnt are used instead, built by main thread.
*_removed are augmented with Query*:Def to allow removal of old {symbol,outline}2refcnt entries.
