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/std/math/log.zig b/std/math/log.zig
index 6bed4c0da1..1cba1138db 100644
--- a/std/math/log.zig
+++ b/std/math/log.zig
@@ -4,7 +4,7 @@ const builtin = @import("builtin");
 const TypeId = builtin.TypeId;
 const assert = std.debug.assert;
 
-pub fn log(comptime T: type, base: T, x: T) -> T {
+pub fn log(comptime T: type, base: T, x: T) T {
     if (base == 2) {
         return math.log2(x);
     } else if (base == 10) {