Adjust README

The README previously suggested that 'clean' code is a necessity for
amenability to verification. This was not intentional, and as noted
in #63, not true.

This commit removes the mentioning of 'clean' code from the README.
The primary qualities that we seek from 'cleanliness' are amenability
for manual audit and adaptability. The former was already mentioned
explicitly in the README, while the latter is added in this commit.

Closes #63

README.md

@@ -5,8 +5,8 @@
 ## Goals of mlkem-c-aarch64
 
 The primary goals of this project are as follows:
-- _Assurance:_ Clean code that's extensively tested and amenable for audit and verification
-- _Ease of use:_ Permissive licensing, modularity, few dependencies
+- _Assurance:_ Offer code that's extensively tested and amenable for audit and verification
+- _Ease of use:_ Permissive licensing, modularity, adaptability, few dependencies
 - _Performance:_ Competitive performance for most Armv8-A/Armv9-A platforms
 
 There are tensions between these goals: