Fix syntax for setting g:solarized_visibility

CHANGELOG.mkd

@@ -86,13 +86,13 @@ These changes may require you to change your configuration.
     displayed using ":set list" can be set to one of three levels depending on 
     your needs.
 
-            g:solarized_visibility =  "normal"|   "high" or "low"
+            let g:solarized_visibility =  "normal"|   "high" or "low"
 
     I'll be honest: I still prefer low visibility. I like them barely there.  
     They show up in lines that are highlighted as by the cursor line, which 
     works for me. If you are with me on this, put the following in your .vimrc:
 
-            g:solarized_visibility =  "low"
+            let g:solarized_visibility =  "low"
 
 ### Non Critical Changes