Update nomenclature to match @Maratyszcza proposal in WebAssembly#127

Author: omnisip

proposals/simd/BinarySIMD.md

@@ -222,4 +222,4 @@ For example, `ImmLaneIdx16` is a byte with values in the range 0-15 (inclusive).
 | `i32x4.trunc_sat_f32x4_u`  |    `0xf9`| -                  |
 | `f32x4.convert_i32x4_s`    |    `0xfa`| -                  |
 | `f32x4.convert_i32x4_u`    |    `0xfb`| -                  |
-| `i16x8.extmul_padd_i8x16_u`|          | -                  |
+| `i16x8.dot_i8x16_u`        |          | -                  |

proposals/simd/ImplementationStatus.md

@@ -190,7 +190,7 @@
 | `i32x4.trunc_sat_f32x4_u`  |               `-msimd128` | :heavy_check_mark: |                    |                    | :heavy_check_mark: |
 | `f32x4.convert_i32x4_s`    |               `-msimd128` | :heavy_check_mark: |                    |                    | :heavy_check_mark: |
 | `f32x4.convert_i32x4_u`    |               `-msimd128` | :heavy_check_mark: |                    |                    | :heavy_check_mark: |
-| `i16x8.extmul_padd_i8x16_u`|                           |                    |                    |                    |                    |
+| `i16x8.dot_i8x16_u`        |                           |                    |                    |                    |                    |
 
 [1] Tip of tree LLVM as of May 20, 2020
 

proposals/simd/SIMD.md

@@ -1026,7 +1026,7 @@ def S.widen_high_T_u(a):
 
 
 ### Horizontal Multiply Extend and Add
-* `i16x8.extmul_padd_i8x16_u(a: v128, b: v128) -> v128`
+* `i16x8.dot_i8x16_u(a: v128, b: v128) -> v128`
 
 Multiplies two u8x16 vectors, temporarily expands the values to two i16x8s, before performing 
 pairwise addition leading to one i16x8/u16x8.