Add known_to_abort documentation (#980)

Author: jgcrosta

apps/nextra/pages/en/build/smart-contracts/linter.mdx

@@ -59,6 +59,16 @@ It is a common Move pattern to provide inline specifications in conditions, espe
 
 Note that an `assert!` is translated to a conditional abort, so blocks in `assert!` condition also are reported by this lint.
 
+### `known_to_abort`
+
+Checks for expressions that will always abort at runtime due to known constant values that violate runtime constraints. This lint helps identify code that will deterministically fail before it reaches production.
+
+The following cases are detected:
+
+- **Bit shifts with excessive shift amounts**: `x << n` or `x >> n` where `n` is a constant that is greater than or equal to the bit width of `x`'s type. For example, `value << 64` when `value` is of type `u64` will always abort.
+- **Division or modulo by zero**: `x / 0` or `x % 0` operations will always abort at runtime.
+- **Out-of-range type casting**: `constant as type` where the `constant` value is outside the representable range of the target `type`. For example, `300 as u8` will abort since `u8` can only represent values 0-255.
+
 ### `needless_bool`
 
 Checks for patterns of the form (where `x` is any arbitrary boolean expression):