[NFC] Improve some lookup-related doc comments

# Conflicts:
#	include/swift/AST/NameLookupRequests.h
#	lib/AST/ModuleNameLookup.cpp

Author: beccadax

include/swift/AST/ModuleNameLookup.h

@@ -41,14 +41,14 @@ enum class ResolutionKind {
 
 void simple_display(llvm::raw_ostream &out, ResolutionKind kind);
 
-/// Performs a lookup into the given module and it's imports.
+/// Performs a lookup into the given module and its imports.
 ///
-/// If 'moduleOrFile' is a ModuleDecl, we search the module and it's
+/// If 'moduleOrFile' is a ModuleDecl, we search the module and its
 /// public imports. If 'moduleOrFile' is a SourceFile, we search the
 /// file's parent module, the module's public imports, and the source
 /// file's private imports.
 ///
-/// \param moduleOrFile The module or file unit whose imports to search.
+/// \param moduleOrFile The module or file unit to search, including imports.
 /// \param name The name to look up.
 /// \param[out] decls Any found decls will be added to this vector.
 /// \param lookupKind Whether this lookup is qualified or unqualified.

include/swift/AST/NameLookupRequests.h

@@ -425,7 +425,21 @@ class LookupInModuleRequest
 private:
   friend SimpleRequest;
 
-  // Evaluation.
+  /// Performs a lookup into the given module and its imports.
+  ///
+  /// If 'moduleOrFile' is a ModuleDecl, we search the module and its
+  /// public imports. If 'moduleOrFile' is a SourceFile, we search the
+  /// file's parent module, the module's public imports, and the source
+  /// file's private imports.
+  ///
+  /// \param evaluator The request evaluator.
+  /// \param moduleOrFile The module or file unit to search, including imports.
+  /// \param name The name to look up.
+  /// \param lookupKind Whether this lookup is qualified or unqualified.
+  /// \param resolutionKind What sort of decl is expected.
+  /// \param moduleScopeContext The top-level context from which the lookup is
+  ///        being performed, for checking access. This must be either a
+  ///        FileUnit or a Module.
   QualifiedLookupResult
   evaluate(Evaluator &evaluator, const DeclContext *moduleOrFile, DeclName name,
            NLKind lookupKind, namelookup::ResolutionKind resolutionKind,

lib/AST/ModuleNameLookup.cpp

@@ -46,10 +46,21 @@ class ModuleNameLookup {
         resolutionKind(resolutionKind),
         respectAccessControl(!ctx.isAccessControlDisabled()) {}
 
-  /// Performs a qualified lookup into the given module and, if necessary, its
-  /// reexports.
+  /// Performs the qualified lookup requested by \p LookupStrategy into the
+  /// given module and, if necessary, its reexports.
   ///
-  /// The results are appended to \p decls.
+  /// If 'moduleOrFile' is a ModuleDecl, we search the module and it's
+  /// public imports. If 'moduleOrFile' is a SourceFile, we search the
+  /// file's parent module, the module's public imports, and the source
+  /// file's private imports.
+  ///
+  /// \param[out] decls Results are appended to this vector.
+  /// \param moduleOrFile The module or file unit to search, including imports.
+  /// \param accessPath The access path that was imported; if not empty, only
+  ///                   the named declaration will be imported.
+  /// \param moduleScopeContext The top-level context from which the lookup is
+  ///        being performed, for checking access. This must be either a
+  ///        FileUnit or a Module.
   void lookupInModule(SmallVectorImpl<ValueDecl *> &decls,
                       const DeclContext *moduleOrFile,
                       ImportPath::Access accessPath,
@@ -68,6 +79,10 @@ class LookupByName : public ModuleNameLookup<LookupByName> {
   const NLKind lookupKind;
 
 public:
+  /// \param ctx The AST context that the lookup will be performed in.
+  /// \param name The name that will be looked up.
+  /// \param lookupKind Whether this lookup is qualified or unqualified.
+  /// \param resolutionKind What sort of decl is expected.
   LookupByName(ASTContext &ctx, ResolutionKind resolutionKind,
                DeclName name, NLKind lookupKind)
     : Super(ctx, resolutionKind), name(name),
@@ -80,6 +95,10 @@ class LookupByName : public ModuleNameLookup<LookupByName> {
     return true;
   }
 
+  /// \param module The module to search for declarations in.
+  /// \param path The access path that was imported; if not empty, only the
+  ///             named declaration will be imported.
+  /// \param[out] localDecls Results are appended to this vector.
   void doLocalLookup(ModuleDecl *module, ImportPath::Access path,
                      SmallVectorImpl<ValueDecl *> &localDecls) {
     // If this import is specific to some named decl ("import Swift.Int")