[general] Switch code block formatting to use fence formatting

Changes:
* Indented code block doesn't support syntax highlighting, use fenced
formatting (```) instead for better syntax highlighting
* Wrap commands/functions in backticks
* Typo fixes

modules/syntax-highlighting/README.md

@@ -22,7 +22,9 @@ Settings
 To enable highlighting for this module only, add the following line to
 *zpreztorc*:
 
-    zstyle ':prezto:module:syntax-highlighting' color 'yes'
+```sh
+zstyle ':prezto:module:syntax-highlighting' color 'yes'
+```
 
 ### Highlighters
 
@@ -31,12 +33,14 @@ only enables the *main* highlighter by default.
 
 To enable all highlighters, add the following to *zpreztorc*:
 
-    zstyle ':prezto:module:syntax-highlighting' highlighters \
-      'main' \
-      'brackets' \
-      'pattern' \
-      'cursor' \
-      'root'
+```sh
+zstyle ':prezto:module:syntax-highlighting' highlighters \
+  'main' \
+  'brackets' \
+  'pattern' \
+  'cursor' \
+  'root'
+```
 
 ### Highlighting Styles
 
@@ -45,10 +49,12 @@ Each syntax highlighter defines styles used to highlight tokens.
 To highlight, for example, builtins, commands, and functions in blue instead of
 green, add the following to *zpreztorc*:
 
-    zstyle ':prezto:module:syntax-highlighting' styles \
-      'builtin' 'bg=blue' \
-      'command' 'bg=blue' \
-      'function' 'bg=blue'
+```sh
+zstyle ':prezto:module:syntax-highlighting' styles \
+  'builtin' 'bg=blue' \
+  'command' 'bg=blue' \
+  'function' 'bg=blue'
+```
 
 Authors
 -------