updated k&r .gitignore, now tracks nested directories

.gitignore

@@ -13,11 +13,11 @@
 # except k&r
 !k\&r/
 # except chapters
-!k\&r/[0-9]*/
+!k\&r/**/[0-9]*/
 # and excercise solutions
-!k\&r/*/[0-9]*.c
+!k\&r/**/[0-9]*.c
 # and header files
-!k\&r/*/*.h
+!k\&r/**/*.h
 
 # ---- udemy c++ .gitignore ----
 # except udemy cpp