Fix lint issues

Author: Gerrit0

src/lib/converter/factories/signature.ts

@@ -354,7 +354,7 @@ function convertTypeParameters(
         const variance = getVariance(declaration?.modifiers);
 
         const paramRefl = new TypeParameterReflection(
-            param.symbol?.name || "__type",
+            param.symbol.name,
             parent,
             variance,
         );

src/lib/converter/symbols.ts

@@ -602,7 +602,7 @@ function convertClassOrInterface(
     // And type arguments
     if (instanceType.typeParameters) {
         reflection.typeParameters = instanceType.typeParameters.map((param) => {
-            const declaration = param.symbol?.declarations?.[0];
+            const declaration = param.symbol.declarations?.[0];
             assert(declaration && ts.isTypeParameterDeclaration(declaration));
             return createTypeParamReflection(declaration, reflectionContext);
         });

src/lib/converter/types.ts

@@ -838,7 +838,7 @@ const mappedConverter: TypeConverter<
         const templateType = convertType(context, type.templateType);
 
         return new MappedType(
-            type.typeParameter.symbol?.name || "__type",
+            type.typeParameter.symbol.name || "__type",
             convertType(context, type.typeParameter.getConstraint()),
             optionalModifier === "+"
                 ? removeUndefined(templateType)