How can I make Sublime Text reload the file being edited?

To re-load the current file, you can revert the file, either through the menu entry File | Revert File or through the command File: Revert (open the command palette by pressing Ctrl+Shift+P and type revert).

To make it easier in the future, you can bind a shortcut to the revert command, for example F5, simply by adding an entry to your key bindings (Preferences | Key Bindings - User):

{
    "keys": ["f5"],
    "command": "revert"
}

Although there is an accepted answer, it requires that we have to refresh manually everytime by pressing F5. Try this package Auto Refresh here. This automatically refreshes the file in x seconds which is configurable.

Though asked more than a year ago: you can also use "File->Reopen with encoding..." command. Note, all your changes made so far will be discarded while performing reload/revert

In addition, I just realized that when switching from the search bar to the main editor panel, it refresh the view.

So ctrl+F then escape.

Not the best, but no configuration or clicking required. Also, I would expect it not to work if you have unsaved edition.