Ensure the exercises use the canonical format

Add the check-exercises.py tool in the new tools directory.  It is used
to check that the exercises are correctly formatted, printing on stderr
the invalid ones and the diff in the unified format.

Update the exercises that don't use the canonical zig fmt format.

Update some patches that cause the generated zig file to be incorrectly
formatted.

1 files changed, 1 insertions, 1 deletions

diff --git a/exercises/069_comptime4.zig b/exercises/069_comptime4.zig
index 004a42c..f4c8bbb 100644
--- a/exercises/069_comptime4.zig
+++ b/exercises/069_comptime4.zig
@@ -16,7 +16,7 @@ const print = @import("std").debug.print;
 pub fn main() void {
     // Here we declare arrays of three different types and sizes
     // at compile time from a function call. Neat!
-    const s1 = makeSequence(u8, 3);  // creates a [3]u8
+    const s1 = makeSequence(u8, 3); // creates a [3]u8
     const s2 = makeSequence(u32, 5); // creates a [5]u32
     const s3 = makeSequence(i64, 7); // creates a [7]i64