Add config hide placeholders type hints

In the inferred type hints, expand the line too long. add config to disable it.

Example
---
```json
{"rust-analyzer.inlayHints.typeHints.hideInferredTypes": true}
```

```rust
use std::collections::HashMap;
fn foo(iter: Vec<Result<HashMap<String, String>, std::io::Error>>) {
    let output = iter.into_iter().collect::<Result<Vec<_>, _>>().unwrap();
}
```

**Before this PR**

```rust
let output: Vec<HashMap<String, String>> = iter.into_iter().collect::<Result<Vec<_ = HashMap<String, String>>, _ = Error>>().unwrap();
```

**After this PR**

```rust
let output: Vec<HashMap<String, String>> = iter.into_iter().collect::<Result<Vec<_>, _>>().unwrap();
```

crates/ide/src/inlay_hints.rs

@@ -320,6 +320,7 @@ pub struct InlayHintsConfig<'a> {
     pub implied_dyn_trait_hints: bool,
     pub lifetime_elision_hints: LifetimeElisionHints,
     pub param_names_for_lifetime_elision_hints: bool,
+    pub hide_inferred_type_hints: bool,
     pub hide_named_constructor_hints: bool,
     pub hide_closure_initialization_hints: bool,
     pub hide_closure_parameter_hints: bool,
@@ -900,6 +901,7 @@ mod tests {
         adjustment_hints_mode: AdjustmentHintsMode::Prefix,
         adjustment_hints_hide_outside_unsafe: false,
         binding_mode_hints: false,
+        hide_inferred_type_hints: false,
         hide_named_constructor_hints: false,
         hide_closure_initialization_hints: false,
         hide_closure_parameter_hints: false,

crates/ide/src/inlay_hints/placeholders.rs

@@ -20,7 +20,7 @@ pub(super) fn type_hints(
     display_target: DisplayTarget,
     placeholder: InferType,
 ) -> Option<()> {
-    if !config.type_hints {
+    if !config.type_hints || config.hide_inferred_type_hints {
         return None;
     }
 
@@ -73,4 +73,22 @@ fn foo() {
 "#,
         );
     }
+
+    #[test]
+    fn hide_inferred_types() {
+        check_with_config(
+            InlayHintsConfig {
+                type_hints: true,
+                hide_inferred_type_hints: true,
+                ..DISABLED_CONFIG
+            },
+            r#"
+struct S<T>(T);
+
+fn foo() {
+    let t: (_, _, [_; _]) = (1_u32, S(2), [false] as _);
+}
+        "#,
+        );
+    }
 }

crates/ide/src/static_index.rs

@@ -183,6 +183,7 @@ impl StaticIndex<'_> {
                     adjustment_hints_hide_outside_unsafe: false,
                     implicit_drop_hints: false,
                     implied_dyn_trait_hints: false,
+                    hide_inferred_type_hints: false,
                     hide_named_constructor_hints: false,
                     hide_closure_initialization_hints: false,
                     hide_closure_parameter_hints: false,

crates/rust-analyzer/src/cli/analysis_stats.rs

@@ -1222,6 +1222,7 @@ impl flags::AnalysisStats {
                     implied_dyn_trait_hints: true,
                     lifetime_elision_hints: ide::LifetimeElisionHints::Always,
                     param_names_for_lifetime_elision_hints: true,
+                    hide_inferred_type_hints: false,
                     hide_named_constructor_hints: false,
                     hide_closure_initialization_hints: false,
                     hide_closure_parameter_hints: false,

crates/rust-analyzer/src/config.rs

@@ -304,6 +304,9 @@ config_data! {
         /// Hide inlay parameter type hints for closures.
         inlayHints_typeHints_hideClosureParameter: bool = false,
 
+        /// Hide inlay type hints for inferred types.
+        inlayHints_typeHints_hideInferredTypes: bool = false,
+
         /// Hide inlay type hints for constructors.
         inlayHints_typeHints_hideNamedConstructor: bool = false,
 
@@ -1937,6 +1940,7 @@ impl Config {
             hide_named_constructor_hints: self
                 .inlayHints_typeHints_hideNamedConstructor()
                 .to_owned(),
+            hide_inferred_type_hints: self.inlayHints_typeHints_hideInferredTypes().to_owned(),
             hide_closure_initialization_hints: self
                 .inlayHints_typeHints_hideClosureInitialization()
                 .to_owned(),

docs/book/src/configuration_generated.md

@@ -1118,6 +1118,13 @@ Default: `false`
 Hide inlay parameter type hints for closures.
 
 
+## rust-analyzer.inlayHints.typeHints.hideInferredTypes {#inlayHints.typeHints.hideInferredTypes}
+
+Default: `false`
+
+Hide inlay type hints for inferred types.
+
+
 ## rust-analyzer.inlayHints.typeHints.hideNamedConstructor {#inlayHints.typeHints.hideNamedConstructor}
 
 Default: `false`

editors/code/package.json

@@ -2466,6 +2466,16 @@
                     }
                 }
             },
+            {
+                "title": "Inlay Hints",
+                "properties": {
+                    "rust-analyzer.inlayHints.typeHints.hideInferredTypes": {
+                        "markdownDescription": "Hide inlay type hints for inferred types.",
+                        "default": false,
+                        "type": "boolean"
+                    }
+                }
+            },
             {
                 "title": "Inlay Hints",
                 "properties": {