syntax: functions require return type. remove `->`

The purpose of this is:

 * Only one way to do things
 * Changing a function with void return type to return a possible
   error becomes a 1 character change, subtly encouraging
   people to use errors.

See #632

Here are some imperfect sed commands for performing this update:

remove arrow:

```
sed -i 's/\(\bfn\b.*\)-> /\1/g' $(find . -name "*.zig")
```

add void:

```
sed -i 's/\(\bfn\b.*\))\s*{/\1) void {/g' $(find ../ -name "*.zig")
```

Some cleanup may be necessary, but this should do the bulk of the work.

1 files changed, 1 insertions, 1 deletions

diff --git a/test/cases/array.zig b/test/cases/array.zig
index bf77e51fee..577161dd16 100644
--- a/test/cases/array.zig
+++ b/test/cases/array.zig
@@ -21,7 +21,7 @@ test "arrays" {
     assert(accumulator == 15);
     assert(getArrayLen(array) == 5);
 }
-fn getArrayLen(a: []const u32) -> usize {
+fn getArrayLen(a: []const u32) usize {
     return a.len;
 }