chore(ALGO_PARAMS.md): Fix typo

Author: PLNech

ALGO_PARAMS.md

@@ -27,5 +27,5 @@ ef_construction leads to longer construction, but better index quality. At some
 not improve the quality of the index. One way to check if the selection of ef_construction was ok is to measure a recall 
 for M nearest neighbor search when ```ef``` =```ef_construction```: if the recall is lower than 0.9, than there is room 
 for improvement.
-* ```num_elements``` - defines the maximum number of elements in the index. The index can be extened by saving/loading(load_index
+* ```num_elements``` - defines the maximum number of elements in the index. The index can be extended by saving/loading (load_index
 function has a parameter which defines the new maximum number of elements).