unstable-book: Update cmse feature descriptions

Author: workingjubilee

src/doc/unstable-book/src/language-features/abi-c-cmse-nonsecure-call.md

@@ -14,8 +14,8 @@ LLVM, the Rust compiler and the linker are providing
 [support](https://developer.arm.com/documentation/ecm0359818/latest/) for the
 TrustZone-M feature.
 
-One of the things provided, with this unstable feature, is the
-`C-cmse-nonsecure-call` function ABI. This ABI is used on function pointers to
+One of the things provided with this unstable feature is the
+"cmse-nonsecure-call" function ABI. This ABI is used on function pointers to
 non-secure code to mark a non-secure function call (see [section
 5.5](https://developer.arm.com/documentation/ecm0359818/latest/) for details).
 
@@ -28,9 +28,6 @@ With this ABI, the compiler will do the following to perform the call:
 To avoid using the non-secure stack, the compiler will constrain the number and
 type of parameters/return value.
 
-The `extern "C-cmse-nonsecure-call"` ABI is otherwise equivalent to the
-`extern "C"` ABI.
-
 <!-- NOTE(ignore) this example is specific to thumbv8m targets -->
 
 ``` rust,ignore
@@ -40,7 +37,7 @@ The `extern "C-cmse-nonsecure-call"` ABI is otherwise equivalent to the
 #[no_mangle]
 pub fn call_nonsecure_function(addr: usize) -> u32 {
     let non_secure_function =
-        unsafe { core::mem::transmute::<usize, extern "C-cmse-nonsecure-call" fn() -> u32>(addr) };
+        unsafe { core::mem::transmute::<usize, extern "cmse-nonsecure-call" fn() -> u32>(addr) };
     non_secure_function()
 }
 ```

src/doc/unstable-book/src/language-features/cmse-nonsecure-entry.md

@@ -14,8 +14,8 @@ LLVM, the Rust compiler and the linker are providing
 [support](https://developer.arm.com/documentation/ecm0359818/latest/) for the
 TrustZone-M feature.
 
-One of the things provided, with this unstable feature, is the
-`C-cmse-nonsecure-entry` ABI. This ABI marks a Secure function as an
+One of the things provided with this unstable feature is the
+"cmse-nonsecure-entry" ABI. This ABI marks a Secure function as an
 entry function (see [section
 5.4](https://developer.arm.com/documentation/ecm0359818/latest/) for details).
 With this ABI, the compiler will do the following:
@@ -30,7 +30,6 @@ Because the stack can not be used to pass parameters, there will be compilation
 errors if:
 * the total size of all parameters is too big (for example more than four 32
   bits integers)
-* the entry function is not using a C ABI
 
 The special symbol `__acle_se_` will be used by the linker to generate a secure
 gateway veneer.
@@ -42,7 +41,7 @@ gateway veneer.
 #![feature(cmse_nonsecure_entry)]
 
 #[no_mangle]
-pub extern "C-cmse-nonsecure-entry" fn entry_function(input: u32) -> u32 {
+pub extern "cmse-nonsecure-entry" fn entry_function(input: u32) -> u32 {
     input + 6
 }
 ```