Capitalize type names in extended-api.md.

The base SIMD.js is captializing all its type names, so this extended
API proposal should use captialized names for its types too.
diff --git a/extended-api.md b/extended-api.md
index dc908f4..06113cb 100644
--- a/extended-api.md
+++ b/extended-api.md
@@ -18,16 +18,16 @@
 Operations which are portable, but with semantic differences
 ------------------------------------------------------------
 
-Primarily, this will use a new `SIMD.relaxed` namespace:
+Primarily, this will use a new `SIMD.Relaxed` namespace:
 
 ```
-SIMD.relaxed.int32x4.fromFloat32x4     // relaxed on NaN or overflow
-SIMD.relaxed.float32x4.max             // relaxed on NaN, 0 and -0 fungible
-SIMD.relaxed.int32x4.shiftLeftByScalar // relaxed on shift count overflow
+SIMD.Relaxed.Int32x4.fromFloat32x4     // relaxed on NaN or overflow
+SIMD.Relaxed.Float32x4.max             // relaxed on NaN, 0 and -0 fungible
+SIMD.Relaxed.Int32x4.shiftLeftByScalar // relaxed on shift count overflow
 ...
 ```
 
-Functions in `SIMD.relaxed` mimic functions in the base API with corresponding names,
+Functions in `SIMD.Relaxed` mimic functions in the base API with corresponding names,
 and provide weaker portability with greater potential for performance, for example by
 having unspecified results if NaN appear in any part of the (implied) computation, by
 treating negative zero as interchangeable with zero, or by having unspecified
@@ -36,16 +36,16 @@
 Note that an implementation in which these are all identical to their corresponding
 functions in the base namespace will be fully conforming.
 
-Accompanying this is a new `SIMD.checked` namespace to help developers find errors:
+Accompanying this is a new `SIMD.Checked` namespace to help developers find errors:
 
 ```
-SIMD.checked.int32x4.fromFloat32x4
-SIMD.checked.float32x4.max
-SIMD.checked.int32x4.shiftLeftByScalar
+SIMD.Checked.Int32x4.fromFloat32x4
+SIMD.Checked.Float32x4.max
+SIMD.Checked.Int32x4.shiftLeftByScalar
 ...
 ```
 
-Functions in `SIMD.checked` all correspond to functions in `SIMD.relaxed` and
+Functions in `SIMD.Checked` all correspond to functions in `SIMD.Relaxed` and
 throw on any value which would produce unspecified results. They may also
 canonicalize negative zero to positive zero. We'll publish a standard polyfill for
 these functions which implementations or users can use if they wish.
@@ -53,22 +53,22 @@
 Operations which are only available on some platforms
 -----------------------------------------------------
 
-Operations from all platforms are collected together in a single `SIMD.universe` namespace:
+Operations from all platforms are collected together in a single `SIMD.Universe` namespace:
 
 ```
-SIMD.universe.float32x4.fma
-SIMD.universe.int32x4.rotateLeft
-SIMD.universe.int32x4.rotateRight
-SIMD.universe.int32x4.signMask        // movmskps on x86
-SIMD.universe.int32x4.bitInsertIfTrue // vbit on ARM
+SIMD.Universe.Float32x4.fma
+SIMD.Universe.Int32x4.rotateLeft
+SIMD.Universe.Int32x4.rotateRight
+SIMD.Universe.Int32x4.signMask        // movmskps on x86
+SIMD.Universe.Int32x4.bitInsertIfTrue // vbit on ARM
 ...
 ```
 
-Unlike in the `SIMD.relaxed` namespace, these operations all have fairly strict
+Unlike in the `SIMD.Relaxed` namespace, these operations all have fairly strict
 semantics.
 
 We'll publish a standard polyfill that will fill in all functions in the
-`SIMD.universe` namespace that the JIT doesn't predefine. This will ensure that
+`SIMD.Universe` namespace that the JIT doesn't predefine. This will ensure that
 programs continue to at least execute across platforms, though of course the
 performance may vary widely.
 
@@ -78,6 +78,6 @@
 SIMD.isFast
 ```
 
-This function takes a single argument, a function in the `SIMD.universe` API,
+This function takes a single argument, a function in the `SIMD.Universe` API,
 and returns a bool indicating whether the given function is "fast" -- roughly
 meaning a single operation in the underlying platform.