docs: spelling and grammar fixes

Signed-off-by: Ville Skyttä <ville.skytta@iki.fi>

gobject/gobject.c

@@ -3895,7 +3895,7 @@ gpointer
  *
  * Using this function on the return value of the user's callback allows
  * the user to do whichever is more convenient for them. The caller will
- * alway receives exactly one full reference to the value: either the
+ * always receives exactly one full reference to the value: either the
  * one that was returned in the first place, or a floating reference
  * that has been converted to a full reference.
  *

gobject/gparam.c

@@ -1337,8 +1337,8 @@ pool_depth_list (gpointer key,
  * the prerequisite class, not from the interface that
  * prerequires it.
  * 
- * also 'depth' isn't a meaningful concept for interface
- * prerequites.
+ * Also 'depth' isn't a meaningful concept for interface
+ * prerequisites.
  */
 static void
 pool_depth_list_for_interface (gpointer key,

gobject/gtype.h

@@ -1095,7 +1095,7 @@ typedef enum    /*< skip >*/
  * @base_finalize: Location of the base finalization function (optional)
  * @class_init: Location of the class initialization function for
  *  classed and instantiatable types. Location of the default vtable 
- *  inititalization function for interface types. (optional) This function 
+ *  initialization function for interface types. (optional) This function
  *  is used both to fill in virtual functions in the class or default vtable, 
  *  and to do type-specific setup such as registering signals and object
  *  properties.

gobject/gvaluearray.c

@@ -71,7 +71,7 @@
  * @value_array: #GValueArray to get a value from
  * @index_: index of the value of interest
  *
- * Return a pointer to the value at @index_ containd in @value_array.
+ * Return a pointer to the value at @index_ contained in @value_array.
  *
  * Returns: (transfer none): pointer to a value at @index_ in @value_array
  *