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, 3 insertions, 3 deletions

diff --git a/std/math/cbrt.zig b/std/math/cbrt.zig
index 9725716f3b..a265392ff7 100644
--- a/std/math/cbrt.zig
+++ b/std/math/cbrt.zig
@@ -8,7 +8,7 @@ const std = @import("../index.zig");
 const math = std.math;
 const assert = std.debug.assert;
 
-pub fn cbrt(x: var) -> @typeOf(x) {
+pub fn cbrt(x: var) @typeOf(x) {
     const T = @typeOf(x);
     return switch (T) {
         f32 => cbrt32(x),
@@ -17,7 +17,7 @@ pub fn cbrt(x: var) -> @typeOf(x) {
     };
 }
 
-fn cbrt32(x: f32) -> f32 {
+fn cbrt32(x: f32) f32 {
     const B1: u32 = 709958130; // (127 - 127.0 / 3 - 0.03306235651) * 2^23
     const B2: u32 = 642849266; // (127 - 127.0 / 3 - 24 / 3 - 0.03306235651) * 2^23
 
@@ -57,7 +57,7 @@ fn cbrt32(x: f32) -> f32 {
     return f32(t);
 }
 
-fn cbrt64(x: f64) -> f64 {
+fn cbrt64(x: f64) f64 {
     const B1: u32 = 715094163;  // (1023 - 1023 / 3 - 0.03306235651 * 2^20
     const B2: u32 = 696219795;  // (1023 - 1023 / 3 - 54 / 3 - 0.03306235651 * 2^20