Reword no-std documentation change from PR 343

Author: dtolnay

README.md

@@ -127,9 +127,9 @@ anyhow = "1.0"
 
 ## No-std support
 
-In no_std mode, the same API is almost entirely available and works the same
-way. To depend on Anyhow in no_std mode, disable our default enabled "std"
-feature in Cargo.toml. A global allocator is required.
+In no_std mode, almost all of the same API is available and works the same way.
+To depend on Anyhow in no_std mode, disable our default enabled "std" feature in
+Cargo.toml. A global allocator is required.
 
 ```toml
 [dependencies]