fix(clang-tidy): fix issues it found in CI

Curiously, the changed includes seem to allow `clang-tidy` to see issues
that it previously didn't see. This commit fixes them.

Signed-off-by: Ingo Müller <ingomueller@google.com>

Author: ingomueller-net

include/substrait/expression/DecimalLiteral.h

@@ -7,7 +7,7 @@
 #include <utility>
 
 namespace substrait::proto {
-class Expression_Literal_Decimal;
+class Expression_Literal_Decimal; // NOLINT
 }
 
 namespace io::substrait::expression {

src/substrait/textplan/parser/SubstraitPlanRelationVisitor.h

@@ -19,9 +19,9 @@
 
 namespace substrait::proto {
 class Expression;
-class Expression_Literal;
-class Expression_Literal_Map_KeyValue;
-class Type_Struct;
+class Expression_Literal; // NOLINT
+class Expression_Literal_Map_KeyValue; // NOLINT
+class Type_Struct; // NOLINT
 } // namespace substrait::proto
 
 namespace io::substrait::textplan {

src/substrait/textplan/parser/SubstraitPlanSubqueryRelationVisitor.h

@@ -19,9 +19,9 @@
 
 namespace substrait::proto {
 class Expression;
-class Expression_Literal;
-class Expression_Literal_Map_KeyValue;
-class Type_Struct;
+class Expression_Literal; // NOLINT
+class Expression_Literal_Map_KeyValue; // NOLINT
+class Type_Struct; // NOLINT
 } // namespace substrait::proto
 
 namespace io::substrait::textplan {