Clear block can be collapsed warnings

Clippy emits:

 warning: this `else { if .. }` block can be collapsed

In one instance the nested if statements assist readability, add allow
attribute. For all other instances collapse the blocks with no loss of
clarity.

Author: tcharding

src/interpreter/inner.rs

@@ -107,6 +107,7 @@ pub(super) enum Inner {
 /// Parses an `Inner` and appropriate `Stack` from completed transaction data,
 /// as well as the script that should be used as a scriptCode in a sighash
 /// Tr outputs don't have script code and return None.
+#[allow(clippy::collapsible_else_if)]
 pub(super) fn from_txdata<'txin>(
     spk: &bitcoin::Script,
     script_sig: &'txin bitcoin::Script,

src/miniscript/types/correctness.rs

@@ -483,14 +483,11 @@ impl Property for Correctness {
                 Input::One | Input::OneNonZero => 1,
                 Input::Any | Input::AnyNonZero => 2, // we only check if num args is max 1
             };
-            if i == 0 {
-                if subtype.base != Base::B {
-                    return Err(ErrorKind::ThresholdBase(i, subtype.base));
-                }
-            } else {
-                if subtype.base != Base::W {
-                    return Err(ErrorKind::ThresholdBase(i, subtype.base));
-                }
+            if i == 0 && subtype.base != Base::B {
+                return Err(ErrorKind::ThresholdBase(i, subtype.base));
+            }
+            if i != 0 && subtype.base != Base::W {
+                return Err(ErrorKind::ThresholdBase(i, subtype.base));
             }
             if !subtype.unit {
                 return Err(ErrorKind::ThresholdNonUnit(i));