Add error messages and fix documentation

plugins/include/cstrike.inc

@@ -354,17 +354,18 @@ native cs_set_c4_defusing(c4index, bool:defusing);
  * Creates an entity using Counter-Strike's custom CreateNamedEntity wrapper.
  *
  * @note Unlike other mods CS keeps track of entities using a custom hashtable.
- *       This function will add entities to this hashtable, providing benefits
- *       over the default engine functions (used by create_entity() for example):
+ *       This function adds entities to this hashtable, providing benefits over
+ *       the default CreateNamedEntity (used by create_entity() for example):
  *       - Storing entities in a hashtable allows CS to improve classname lookup
- *         performance compared to functions like FindEntityByString that usually
- *         have to loop incrementally through all entities.
+ *         performance compared to functions like FindEntityByString (used by
+ *         find_ent_by_class() for example) that usually have to loop
+ *         through all entities incrementally.
  *       - As CS exclusively uses the hashtable for classname lookup, entities
  *         created using the default engine functions will not be found by the
  *         game. For example "weaponbox" entities are supposed to be
  *         automatically cleaned up on round restart but are not considered if
  *         they have not been added to the hashtable.
- * @note CS's faster hashtable lookup can be utilized with cs_find_ent_by_class()
+ * @note The faster hashtable lookup can be utilized with cs_find_ent_by_class()
  *
  * @param classname     Entity class name
  *
@@ -372,14 +373,14 @@ native cs_set_c4_defusing(c4index, bool:defusing);
  */
 native cs_create_entity(const classname[]);
 
-/** 
+/**
  * Finds an entity in the world using Counter-Strike's custom FindEntityByString
  * wrapper.
  *
  * @note Unlike other mods CS keeps track of entities using a custom hashtable.
- *       This function utilizes the custom hasthable and allows for considerably
- *       faster classname lookup compared to the default engine functions (used
- *       by find_ent_by_class() for example).
+ *       This function utilizes the hasthable and allows for considerably faster
+ *       classname lookup compared to the default FindEntityByString (used by
+ *       find_ent_by_class() for example).
  * @note This exclusively considers entities in the hashtable, created by the
  *       game itself or using cs_create_entity().
  *