simplify syntax

as per rust-lang/rust#18253

Author: steveklabnik

index.html

@@ -289,7 +289,7 @@ <h1 id="safety?-15" class='section-header'><a
         <span class='ident'>spawn</span>(<span class='kw'>proc</span>() {
             <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>array</span> <span class='op'>=</span> <span class='ident'>number</span>.<span class='ident'>lock</span>();
 
-            <span class='op'>*</span>(<span class='ident'>array</span>.<span class='ident'>get_mut</span>(<span class='ident'>i</span>)) <span class='op'>+=</span> <span class='number'>1</span>;
+            (<span class='op'>*</span><span class='ident'>array</span>)[<span class='ident'>i</span>] <span class='op'>+=</span> <span class='number'>1</span>;
 
             <span class='macro'>println</span><span class='macro'>!</span>(<span class='string'>&quot;numbers[{}] is {}&quot;</span>, <span class='ident'>i</span>, (<span class='op'>*</span><span class='ident'>array</span>)[<span class='ident'>i</span>]);
         });
@@ -317,7 +317,7 @@ <h1 id="safety?-17" class='section-header'><a
 <span class='ident'>spawn</span>(<span class='kw'>proc</span>() {
     <span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>array</span> <span class='op'>=</span> <span class='ident'>number</span>.<span class='ident'>lock</span>();
 
-    <span class='op'>*</span>(<span class='ident'>array</span>.<span class='ident'>get_mut</span>(<span class='ident'>i</span>)) <span class='op'>+=</span> <span class='number'>1</span>;
+    (<span class='op'>*</span><span class='ident'>array</span>)[<span class='ident'>i</span>] <span class='op'>+=</span> <span class='number'>1</span>;
 
     <span class='macro'>println</span><span class='macro'>!</span>(<span class='string'>&quot;numbers[{}] is {}&quot;</span>, <span class='ident'>i</span>, (<span class='op'>*</span><span class='ident'>array</span>)[<span class='ident'>i</span>]);
 });

index.md

@@ -213,7 +213,7 @@ fn main() {
         spawn(proc() {
             let mut array = number.lock();
 
-            *(array.get_mut(i)) += 1;
+            (*array)[i] += 1;
 
             println!("numbers[{}] is {}", i, (*array)[i]);
         });
@@ -243,7 +243,7 @@ fn main() {
 spawn(proc() {
     let mut array = number.lock();
 
-    *(array.get_mut(i)) += 1;
+    (*array)[i] += 1;
 
     println!("numbers[{}] is {}", i, (*array)[i]);
 });