docs: Fix minor typos in Comparator and grabber.sh

Author: apebl

grabber.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 
-# An utility script to grab source files
+# A utility script to grab source files
 #
 # example:
 # grabber.sh src/*.vala

src/Comparator.vala

@@ -22,7 +22,7 @@ using Gee;
 
 namespace Gpseq {
 	/**
-	 * An utility object for sort.
+	 * A utility object for sort.
 	 */
 	internal class Comparator<G> : Object {
 		private CompareDataFunc<G> _compare_func;