libobs: Fix comment typo

verison -> version
As a drive-by, also changes null to NULL.

libobs/obs-module.h

@@ -180,8 +180,8 @@ MODULE_EXPORT const char *obs_module_name(void);
 /** Optional: Returns a description of the module */
 MODULE_EXPORT const char *obs_module_description(void);
 
-/** Returns the module's unique ID, or null if it doesn't have one */
+/** Returns the module's unique ID, or NULL if it doesn't have one */
 MODULE_EXPORT const char *obs_get_module_id(obs_module_t *module);
 
-/** Returns the module's semver verison number or null if it doesn't have one */
+/** Returns the module's semver version number or NULL if it doesn't have one */
 MODULE_EXPORT const char *obs_get_module_version(obs_module_t *module);