Fix Markdown list formatting.

The Markdown engine used by the book can cope with a single leading space
on the list marker:

    Like this:

     * List item

    Rather than like this:

    * List item

… but it’s not the typical convention employed in the book, and moreover
the Markdown engine used for producing the error index *can’t* cope with
it (its behaviour looks like a bug, as it appears to lose one of the two
line breaks as well, but that’s immaterial here).

So, we shift to a single convention which doesn’t trigger bugs in the
Markdown renderer.

src/doc/book/casting-between-types.md

@@ -16,18 +16,18 @@ function result.
 
 The most common case of coercion is removing mutability from a reference:
 
- * `&mut T` to `&T`
+* `&mut T` to `&T`
 
 An analogous conversion is to remove mutability from a
 [raw pointer](raw-pointers.md):
 
- * `*mut T` to `*const T`
+* `*mut T` to `*const T`
 
 References can also be coerced to raw pointers:
 
- * `&T` to `*const T`
+* `&T` to `*const T`
 
- * `&mut T` to `*mut T`
+* `&mut T` to `*mut T`
 
 Custom coercions may be defined using [`Deref`](deref-coercions.md).
 
@@ -59,11 +59,11 @@ A cast `e as U` is valid if `e` has type `T` and `T` *coerces* to `U`.
 
 A cast `e as U` is also valid in any of the following cases:
 
- * `e` has type `T` and `T` and `U` are any numeric types; *numeric-cast*
- * `e` is a C-like enum (with no data attached to the variants),
-    and `U` is an integer type; *enum-cast*
- * `e` has type `bool` or `char` and `U` is an integer type; *prim-int-cast*
- * `e` has type `u8` and `U` is `char`; *u8-char-cast*
+* `e` has type `T` and `T` and `U` are any numeric types; *numeric-cast*
+* `e` is a C-like enum (with no data attached to the variants),
+   and `U` is an integer type; *enum-cast*
+* `e` has type `bool` or `char` and `U` is an integer type; *prim-int-cast*
+* `e` has type `u8` and `U` is `char`; *u8-char-cast*
 
 For example
 

src/librustc_metadata/diagnostics.rs

@@ -57,9 +57,9 @@ An unknown "kind" was specified for a link attribute. Erroneous code example:
 
 Please specify a valid "kind" value, from one of the following:
 
- * static
- * dylib
- * framework
+* static
+* dylib
+* framework
 
 "##,
 

src/librustc_typeck/diagnostics.rs

@@ -1378,8 +1378,8 @@ let x = |_| {}; // error: cannot determine a type for this expression
 
 You have two possibilities to solve this situation:
 
- * Give an explicit definition of the expression
- * Infer the expression
+* Give an explicit definition of the expression
+* Infer the expression
 
 Examples: