Revert "set all enum to be snake_case when serializing"

This reverts commit 83f6c2f265.

query-grammar/src/occur.rs

@@ -6,7 +6,6 @@ use serde::Serialize;
 /// Defines whether a term in a query must be present,
 /// should be present or must not be present.
 #[derive(Debug, Clone, Hash, Copy, Eq, PartialEq, Serialize)]
-#[serde(rename_all_fields = "snake_case")]
 pub enum Occur {
     /// For a given document to be considered for scoring,
     /// at least one of the queries with the Should or the Must

query-grammar/src/query_grammar.rs

@@ -797,7 +797,6 @@ fn operand_occur_leaf_infallible(
 }
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
-#[serde(rename_all_fields = "snake_case")]
 enum BinaryOperand {
     Or,
     And,

query-grammar/src/user_input_ast.rs

@@ -6,7 +6,6 @@ use serde::Serialize;
 use crate::Occur;
 
 #[derive(PartialEq, Clone, Serialize)]
-#[serde(rename_all_fields = "snake_case")]
 pub enum UserInputLeaf {
     Literal(UserInputLiteral),
     All,
@@ -111,7 +110,6 @@ impl Debug for UserInputLeaf {
 }
 
 #[derive(Copy, Clone, Eq, PartialEq, Debug, Serialize)]
-#[serde(rename_all_fields = "snake_case")]
 pub enum Delimiter {
     SingleQuotes,
     DoubleQuotes,
@@ -157,7 +155,6 @@ impl fmt::Debug for UserInputLiteral {
 }
 
 #[derive(PartialEq, Debug, Clone, Serialize)]
-#[serde(rename_all_fields = "snake_case")]
 pub enum UserInputBound {
     Inclusive(String),
     Exclusive(String),
@@ -193,7 +190,6 @@ impl UserInputBound {
 }
 
 #[derive(PartialEq, Clone, Serialize)]
-#[serde(rename_all_fields = "snake_case")]
 pub enum UserInputAst {
     Clause(Vec<(Option<Occur>, UserInputAst)>),
     Leaf(Box<UserInputLeaf>),