message: do not read data/packagenames.json
diff: import * as vscode from 'vscode'
  import * as cp from 'child_process'
  -import * as fs from 'fs'
  import {Extension} from 'src/main'
  -type Packages = {[key: string]: {command: string, detail: string, documentation: string}}
  -
  export class TeXDoc {
  extension: Extension
  - pkgs: Packages = {}
  - packageItems: vscode.QuickPickItem[] = []
  constructor(e: Extension) {
  this.extension = e
  - setImmediate( () => this.readPackages() )
  - }
  -
  - private readPackages() {
  - const json = fs.readFileSync(`${this.extension.extensionRoot}/data/packagenames.json`).toString()
  - const items: vscode.QuickPickItem[] = []
  - const pkgs: Packages = JSON.parse(json)
  - for ( const pkg of Object.values(pkgs) ) {
  - const item = this.quickItemize(pkg)
  - if (item) {
  - items.push(item)
  - }
  - }
  - this.packageItems = items
  - this.pkgs = pkgs
  - }
  -
  - private quickItemize(pkg: Packages[string]) {
  - if ( !(pkg.command && pkg.documentation) ) {
  - return undefined
  - } else {
  - return { label: pkg.command, detail: pkg.documentation }
  - }
  }
  private runTexdoc(pkg: string) {
  @@ -89,7 +61,6 @@ export class TeXDoc {
  }
  texdocUsepackages() {
  - const items: vscode.QuickPickItem[] = []
  let names: string[] = []
  for (const tex of this.extension.manager.getIncludedTeX()) {
  const content = this.extension.manager.cachedContent[tex]
  @@ -100,14 +71,9 @@ export class TeXDoc {
  names = names.concat(pkgs)
  }
  const packagenames = Array.from(new Set(names))
  - for (const name of packagenames) {
  - let item: vscode.QuickPickItem | undefined = { label: name }
  - const pkg = this.pkgs[name]
  - if (pkg) {
  - item = this.quickItemize(pkg) || item
  - }
  - items.push(item)
  - }
  + const items: vscode.QuickPickItem[] = packagenames.map( name => {
  + return { label: name }
  + })
  vscode.window.showQuickPick(items).then(selectedPkg => {
  if (!selectedPkg) {
  return
  