docs: adding better readme to vscode extension

Author: benfdking

vscode/extension/README.md

@@ -1 +1,28 @@
 # SQLMesh VSCode Extension
+
+## Functionality
+
+The following section outlines all the functionality in the Visual Studio Code extension. It is broken up into logical sections. 
+
+### Authentication 
+
+The extension allows you to manage your tcloud session within visual studio code 
+
+- Sign in 
+- Sign out 
+- Sign in with specified flow
+
+Can see in the bottom left your user account.
+
+### Formatting 
+
+The extension allows you to:
+
+- format individual documents explicitely 
+- format individual documents on save
+- format a whole project
+
+### Linting 
+
+The extension allows you to see linting errors and warnings in line.
+