issue #40793

Correcting the two mistakes in the README.md

Author: GAJaloyan

src/librustc_borrowck/borrowck/README.md

@@ -347,7 +347,7 @@ ALIASABLE(*LV, MQ)                 // M-Deref-Unique
   ALIASABLE(LV, MQ)
 ```
 
-### Checking mutability of immutable pointer types
+### Checking aliasability of immutable pointer types
 
 Immutable pointer types like `&T` are aliasable, and hence can only be
 borrowed immutably:
@@ -357,7 +357,7 @@ ALIASABLE(*LV, imm)                // M-Deref-Borrowed-Imm
   TYPE(LV) = &Ty
 ```
 
-### Checking mutability of mutable pointer types
+### Checking aliasability of mutable pointer types
 
 `&mut T` can be frozen, so it is acceptable to borrow it as either imm or mut: