title: Reading & writing data to a .txt file using vscode extension api
body: <p>So I am new to this vscode extension api. I have this functionality where I need to take input from the user when they click on certain line and then get the <code>1). input value, line number and file name</code> and <code>2). store it to a text file</code>.</p>
  <p>I am done with the first part, I am getting the data everything. Now I have to just write it to the file and if there is data already, new data should be appended not overwritten.</p>
  <p>I have tried using <code>fs.writeFileSync(filePath, data) and readFileSync</code> but nothing, I do not know if I am doing it correctly. If someone can point me in the right direction I am just blank at this stage?</p>
  <p>Any help would be appreciated, Thanks in advance.</p>