make load_context_path/2 handle .pl file extensions, remove commented out code

src/clause_types.rs

@@ -150,11 +150,6 @@ impl InlinedClauseType {
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 pub enum SystemClauseType {
-    // AbolishClause,
-    // AbolishModuleClause,
-    // AssertDynamicPredicateToBack,
-    // AssertDynamicPredicateToFront,
-    // AtEndOfExpansion,
     AtomChars,
     AtomCodes,
     AtomLength,
@@ -189,8 +184,6 @@ pub enum SystemClauseType {
     DynamicModuleResolution(usize),
     EnqueueAttributeGoal,
     EnqueueAttributedVar,
-//  ExpandGoal,
-//  ExpandTerm,
     FetchGlobalVar,
     FetchGlobalVarWithOffset,
     FirstStream,
@@ -207,16 +200,13 @@ pub enum SystemClauseType {
     GetAttrVarQueueDelimiter,
     GetAttrVarQueueBeyond,
     GetBValue,
-//  GetClause,
     GetContinuationChunk,
-//  GetModuleClause,
     GetNextDBRef,
     GetNextOpDBRef,
     IsPartialString,
     LookupDBRef,
     LookupOpDBRef,
     Halt,
-//  ModuleHeadIsDynamic,
     GetLiftedHeapFromOffset,
     GetLiftedHeapFromOffsetDiff,
     GetSCCCleaner,
@@ -225,10 +215,7 @@ pub enum SystemClauseType {
     InstallInferenceCounter,
     LiftedHeapLength,
     LoadLibraryAsStream,
-    // ModuleAssertDynamicPredicateToFront,
-    // ModuleAssertDynamicPredicateToBack,
     ModuleExists,
-    // ModuleRetractClause,
     NextEP,
     NoSuchPredicate,
     NumberToChars,
@@ -254,7 +241,6 @@ pub enum SystemClauseType {
     ResetContinuationMarker,
     ResetGlobalVarAtKey,
     ResetGlobalVarAtOffset,
-    // RetractClause,
     RestoreCutPolicy,
     SetCutPoint(RegType),
     SetInput,