Fix typo GH-47

Author: pintergreg

lectures/summary_week10.md

@@ -155,7 +155,7 @@ these are from the book _xUnit test patterns: Refactoring test code_ -- by Gerar
 :::::::::::: {.columns}
 ::::::::: {.column width="55%" .mt-5}
 - write test _before_ writing the tested code
-- without the called unit the test fill fail
+- without the called unit the test will fail
     - the called function does not exist
 - write code, that makes the test pass
 - improve the code quality