Ensure braces are always added for blocks

Code such as `if (foo) foo++;` may seem safe at first but when
nested among other code, especially other conditionals, or complex
expressions, it can become very difficult to scan, leading to
misinterpretation of the code, bugs when editing, etc.

Ensuring consistent use of braces for blocks avoids unintended
changes in behaviour when adding additional statements to the block
as well as encouraging clearer formatting that makes the code easier
to scan. Seeing clusters of braces also serves as an indication to
developers that code complexity may be increasing and is something
that should be addressed.

.eslintrc.js

@@ -26,6 +26,7 @@ module.exports = {
       "react"
   ],
   "rules": {
+    "curly": ["error", "all"],
     "import/prefer-default-export": "off",
     "jsx-a11y/anchor-is-valid": "off",
     "no-case-declarations": "off",