what numbers shows besides file in vs code code example

Example 1: multiple word select in vs code

//Selects the word at the cursor, or the next occurrence of the current selection.
Ctrl+D 

//To add cursors to all the occurrences of a highlighted word 
Ctrl+Shift+L 
//Then select all occurrences of that word

Example 2: vscode search in folder

concatMap(rootTemplate =>
  this.templateEngine.getAllChildTemplates(rootTemplate).pipe(
    map(childTemplates => [rootTemplate, childTemplates])
  )
),
concatMap(([rootTemplate, childTemplates]) => 
  this.templateEngine.createTemplateToRender(childTemplates, rootTemplate)
)