KCL parser: Allow .prop or [index] to follow any expression (#7371)

Previously in a member expression like `foo.x` or `foo[3]`, `foo` had to be an identifier. You could not do something like `f().x` (and if you tried, you got a cryptic error). Rather than make the error better, we should just accept any expression to be the LHS of a member expression (aka its 'object').

This does knock our "parse lots of function calls" from 58 to 55 calls before it stack overflows. But I think it's fine, we'll address this in https://github.com/KittyCAD/modeling-app/pull/6226 when I get back to it.

Closes https://github.com/KittyCAD/modeling-app/issues/7273

rust/kcl-lib/src/parsing/ast/digest.rs

@@ -4,7 +4,7 @@ use crate::parsing::ast::types::{
     Annotation, ArrayExpression, ArrayRangeExpression, AscribedExpression, BinaryExpression, BinaryPart, BodyItem,
     CallExpressionKw, DefaultParamVal, ElseIf, Expr, ExpressionStatement, FunctionExpression, FunctionType, Identifier,
     IfExpression, ImportItem, ImportSelector, ImportStatement, ItemVisibility, KclNone, LabelledExpression, Literal,
-    LiteralIdentifier, LiteralValue, MemberExpression, MemberObject, Name, ObjectExpression, ObjectProperty, Parameter,
+    LiteralIdentifier, LiteralValue, MemberExpression, Name, ObjectExpression, ObjectProperty, Parameter,
     PipeExpression, PipeSubstitution, PrimitiveType, Program, ReturnStatement, TagDeclarator, Type, TypeDeclaration,
     UnaryExpression, VariableDeclaration, VariableDeclarator, VariableKind,
 };
@@ -167,15 +167,6 @@ impl BinaryPart {
     }
 }
 
-impl MemberObject {
-    pub fn compute_digest(&mut self) -> Digest {
-        match self {
-            MemberObject::MemberExpression(me) => me.compute_digest(),
-            MemberObject::Identifier(id) => id.compute_digest(),
-        }
-    }
-}
-
 impl LiteralIdentifier {
     pub fn compute_digest(&mut self) -> Digest {
         match self {