doc: use consistent path in example code

Previous section of documentation said that if GOPATH is not set then
it will be default to "$HOME/go", not "$HOME/work".

This change fix the path in example code to "$HOME/go", and while at it
fix the output of git command after commit.

Change-Id: Ifedca6c3997efd07e865c27b7321d755acad0254
Reviewed-on: https://go-review.googlesource.com/c/go/+/175258Reviewed-by: Andrew Bonventre <andybons@golang.org>

doc/code.html

@@ -304,12 +304,12 @@ optional: you do not need to use source control to write Go code.
 <pre>
 $ <b>cd $GOPATH/src/github.com/user/hello</b>
 $ <b>git init</b>
-Initialized empty Git repository in /home/user/work/src/github.com/user/hello/.git/
+Initialized empty Git repository in /home/user/go/src/github.com/user/hello/.git/
 $ <b>git add hello.go</b>
 $ <b>git commit -m "initial commit"</b>
 [master (root-commit) 0b4507d] initial commit
- 1 file changed, 1 insertion(+)
-  create mode 100644 hello.go
+ 1 file changed, 7 insertion(+)
+ create mode 100644 hello.go
 </pre>
 
 <p>