[AST] Mark '_functionBuilder' attribute as 'UserInaccessible' for now (#32480)

This makes sure that it doesn't show up in code completion

Author: theblixguy

include/swift/AST/Attr.def

@@ -494,7 +494,7 @@ SIMPLE_DECL_ATTR(_disfavoredOverload, DisfavoredOverload,
   ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
   87)
 SIMPLE_DECL_ATTR(_functionBuilder, FunctionBuilder,
-  OnNominalType |
+  OnNominalType | UserInaccessible |
   ABIStableToAdd | ABIStableToRemove | APIStableToAdd | APIStableToRemove,
   88)
 DECL_ATTR(_projectedValueProperty, ProjectedValueProperty,

test/IDE/complete_decl_attribute.swift

@@ -88,7 +88,6 @@ struct MyStruct {}
 // KEYWORD3-NEXT:             Keyword/None:                       NSApplicationMain[#Class Attribute#]; name=NSApplicationMain{{$}}
 // KEYWORD3-NEXT:             Keyword/None:                       usableFromInline[#Class Attribute#]; name=usableFromInline
 // KEYWORD3-NEXT:             Keyword/None:                       propertyWrapper[#Class Attribute#]; name=propertyWrapper
-// KEYWORD3-NEXT:             Keyword/None:                       _functionBuilder[#Class Attribute#]; name=_functionBuilder
 // KEYWORD3-NEXT:             End completions
 
 @#^KEYWORD3_2^#IB class C2 {}
@@ -104,7 +103,6 @@ struct MyStruct {}
 // KEYWORD4-NEXT:             Keyword/None:                       usableFromInline[#Enum Attribute#]; name=usableFromInline
 // KEYWORD4-NEXT:             Keyword/None:                       frozen[#Enum Attribute#]; name=frozen
 // KEYWORD4-NEXT:             Keyword/None:                       propertyWrapper[#Enum Attribute#]; name=propertyWrapper
-// KEYWORD4-NEXT:             Keyword/None:                       _functionBuilder[#Enum Attribute#]; name=_functionBuilder
 // KEYWORD4-NEXT:             End completions
 
 
@@ -117,7 +115,6 @@ struct MyStruct {}
 // KEYWORD5-NEXT:             Keyword/None:                       usableFromInline[#Struct Attribute#]; name=usableFromInline
 // KEYWORD5-NEXT:             Keyword/None:                       frozen[#Struct Attribute#]; name=frozen
 // KEYWORD5-NEXT:             Keyword/None:                       propertyWrapper[#Struct Attribute#]; name=propertyWrapper
-// KEYWORD5-NEXT:             Keyword/None:                       _functionBuilder[#Struct Attribute#]; name=_functionBuilder
 // KEYWORD5-NEXT:             End completions
 
 @#^ON_GLOBALVAR^# var globalVar
@@ -243,7 +240,6 @@ struct _S {
 // ON_MEMBER_LAST-DAG: Keyword/None:                       GKInspectable[#Declaration Attribute#]; name=GKInspectable
 // ON_MEMBER_LAST-DAG: Keyword/None:                       IBSegueAction[#Declaration Attribute#]; name=IBSegueAction
 // ON_MEMBER_LAST-DAG: Keyword/None:                       propertyWrapper[#Declaration Attribute#]; name=propertyWrapper
-// ON_MEMBER_LAST-DAG: Keyword/None:                       _functionBuilder[#Declaration Attribute#]; name=_functionBuilder
 // ON_MEMBER_LAST-DAG: Keyword/None:                       differentiable[#Declaration Attribute#]; name=differentiable
 // ON_MEMBER_LAST-DAG: Keyword/None:                       derivative[#Declaration Attribute#]; name=derivative
 // ON_MEMBER_LAST-DAG: Keyword/None:                       transpose[#Declaration Attribute#]; name=transpose
@@ -290,7 +286,6 @@ func dummy2() {}
 // KEYWORD_LAST-NEXT:             Keyword/None:                       GKInspectable[#Declaration Attribute#]; name=GKInspectable{{$}}
 // KEYWORD_LAST-NEXT:             Keyword/None:                       frozen[#Declaration Attribute#]; name=frozen
 // KEYWORD_LAST-NEXT:             Keyword/None:                       propertyWrapper[#Declaration Attribute#]; name=propertyWrapper
-// KEYWORD_LAST-NEXT:             Keyword/None:                       _functionBuilder[#Declaration Attribute#]; name=_functionBuilder{{$}}
 // KEYWORD_LAST-NEXT:             Keyword/None:                       differentiable[#Declaration Attribute#]; name=differentiable
 // KEYWORD_LAST-NEXT:             Keyword/None:                       IBSegueAction[#Declaration Attribute#]; name=IBSegueAction{{$}}
 // KEYWORD_LAST-NEXT:             Keyword/None:                       derivative[#Declaration Attribute#]; name=derivative