reverse-string: rename function to reversal

exercises/practice/reverse-string/.meta/example.fut

@@ -1,2 +1,2 @@
-def reverse [n] (str: [n]u8): [n]u8 =
+def reversal [n] (str: [n]u8): [n]u8 =
   map (\i -> str[n -i - 1]) (0..<n)

exercises/practice/reverse-string/reverse_string.fut

@@ -1,2 +1,2 @@
-def reverse [n] (str: [n]u8): [n]u8 = ???
+def reversal [n] (str: [n]u8): [n]u8 = ???
 

exercises/practice/reverse-string/test.fut

@@ -31,4 +31,4 @@ import "reverse_string"
 -- output { "reward" }
 
 let main (str: []u8): []u8 =
-  reverse str
+  reversal str

generators/exercises/reverse_string.py

@@ -8,4 +8,4 @@ def gen_test_case(prop, description, inp, expected, f):
 
 def gen_main(f):
     f.write("let main (str: []u8): []u8 =\n")
-    f.write("  reverse str\n")
+    f.write("  reversal str\n")