BE: remove DiagnosticCode::UnusedIncludeDeprecated

Summary: Fully remove this diagnostic code, as it is not relevant any more.

Reviewed By: robertoaloi

Differential Revision: D55186599

fbshipit-source-id: c7612e2c1efc88063bedc1a37d6e2045191fed19

crates/ide_db/src/diagnostic_code.rs

@@ -31,7 +31,6 @@ pub enum DiagnosticCode {
     MissingModule,
     ModuleMismatch,
     UnusedInclude,
-    UnusedIncludeDeprecated,
     BoundVarInPattern,
     UnusedMacro,
     UnusedRecordField,
@@ -118,7 +117,6 @@ impl DiagnosticCode {
             DiagnosticCode::Unexpected(_) => "W0018".to_string(), // unexpected_semi, unexpected_dot
             DiagnosticCode::ExpressionCanBeSimplified => "W0019".to_string(), // expression-can-be-simplified
             DiagnosticCode::UnusedInclude => "W0020".to_string(), // Unused include (previously known as L1500 due to a bug)
-            DiagnosticCode::UnusedIncludeDeprecated => "L1500".to_string(), // Unused include (deprecated, replaced by W0020)
             DiagnosticCode::CannotEvaluateCTCallbacks => "W0021".to_string(),
             DiagnosticCode::MeckMissingNoLinkInInitPerSuite => "W0022".to_string(),
             DiagnosticCode::AtomsExhaustion => "W0023".to_string(),
@@ -134,7 +132,6 @@ impl DiagnosticCode {
             DiagnosticCode::DefaultCodeForEnumIter => "DEFAULT-UNUSED-CONSTRUCTOR".to_string(),
             DiagnosticCode::MissingModule => "missing_module".to_string(),
             DiagnosticCode::UnusedInclude => "unused_include".to_string(),
-            DiagnosticCode::UnusedIncludeDeprecated => "unused_include_deprecated".to_string(),
             DiagnosticCode::HeadMismatch => "head_mismatch".to_string(),
             DiagnosticCode::SyntaxError => "syntax_error".to_string(),
             DiagnosticCode::BoundVarInPattern => "bound_var_in_pattern".to_string(),