run_wptexturize filters whether to skip running wptexturize().
Passing false to the filter will effectively short-circuit wptexturize() returning the original text passed to the function instead.
The filter runs only once, the first time wptexturize() is called.
Use __return_false() to turn off wptexturize().
add_filter( 'run_wptexturize', '__return_false' );
Since: 4.0
run_wptexturize is located in wp-includes/formatting.php