message: Add log messages when executing syncTeXExternal
diff: @@ -440,6 +440,10 @@ export class Locator {
  const configuration = vscode.workspace.getConfiguration('latex-workshop')
  const command = configuration.get('view.pdf.external.synctex.command') as string
  let args = configuration.get('view.pdf.external.synctex.args') as string[]
  + if (command === '') {
  + this.extension.logger.addLogMessage('Error: the external SyncTeX command is an empty string. See view.pdf.external.synctex.command')
  + return
  + }
  if (args) {
  args = args.map(arg => {
  return replaceArgumentPlaceholders(rootFile, this.extension.builder.tmpDir)(arg)
  @@ -448,6 +452,7 @@ export class Locator {
  .replace(/%TEX%/g, texFile)
  })
  }
  + this.extension.logger.addLogMessage(`Execute external SyncTeX command: command ${command}, args ${args}`)
  this.extension.manager.setEnvVar()
  cp.spawn(command, args)
  this.extension.logger.addLogMessage(`Open external viewer for syncTeX from ${pdfFile}`)
  