Use |NimSkull| in the new text. Fix formatting.

doc/tut1.rst

@@ -879,26 +879,26 @@ whose value is then returned implicitly.
 Funcs and methods
 -----------------
 
-As mentioned in the introduction, Nim differentiates between procedures,
+As mentioned in the introduction, |NimSkull| differentiates between procedures,
 functions, and methods, defined by the `proc`, `func`, and `method` keywords
-respectively. In some ways, Nim is a bit more pedantic in its definitions than
-other languages.
+respectively. In some ways, |NimSkull| is a bit more pedantic in its definitions
+than other languages.
 
 Functions are essentially procedures with additional limitations set on them:
 they can't access global state (except `const`) and can't produce side-effects.
-This puts Nim functions closer to the concept of a mathematical function, which
-might be familiar to you if you've ever done functional programming. The main
-benefit of the imposed limits is that it's much easier to reason about the code
-with minimized interdependence of its various parts, as data flows directly
+This puts |NimSkull| functions closer to the concept of a mathematical function,
+which might be familiar to you if you've ever done functional programming. The
+main benefit of the imposed limits is that it's much easier to reason about the
+code with minimized interdependence of its various parts, as data flows directly
 through a function from its arguments to its output. The other notable advantage
 is that the self-contained nature of a function makes it inherently more
 portable and easier to test.
 
-Even though these benefits apply to Nim functions, it's important to keep in
-mind that a `func` can still change its mutable arguments: those marked as `var`
-along with `ref` objects (which possess interior mutability). This still allows
-functions to have additional outputs beside the return value, making them not as
-"pure" as their mathematical counterparts.
+Even though these benefits apply to |NimSkull| functions, it's important to keep
+in mind that a `func` can still change its mutable arguments: those marked as
+`var` along with `ref` objects (which possess interior mutability). This still
+allows functions to have additional outputs beside the return value, making them
+not as "pure" as their mathematical counterparts.
 
 Technically, the `func` keyword is a shorthand alias for `proc` tagged with
 `{.noSideEffects.}`.