Merge #18508: RPC: Fix more formatting nits

f32ab44 Bugfix: RPC: JSON null is not "None" (Luke Dashjr)
26dcf39 Bugfix: RPC: Don't use a continuation elipsis after an elision elipsis (Luke Dashjr)
eca65ca Bugfix: RPC: Add missing commas and correct indentation of explicit ELISION (Luke Dashjr)

Pull request description:

  1. listsinceblock had a double ellipsis (elision + continuation); this looks ugly, just one is needed.
  2. Elision ellipsis wasn't getting a comma, so was truncated to `".."` by comma-removal code.
  3. Elision ellipsis was indented incorrectly (as if it was a subitem).
  4. Similarly, type "none" would get truncated to `"Non"`, when it should really be `"null"` anyway.

ACKs for top commit:
  MarcoFalke:
    ACK f32ab44 🐰

Tree-SHA512: 34e1c72673790ed11cdee838d64ea5e0ac498de19258df99d54b5322e003060123c65ad27ac2fd4729a1dfe52066a0629602a132b1ef85d4154affd99a065a3f

Author: MarcoFalke

src/rpc/util.cpp

@@ -606,11 +606,11 @@ void RPCResult::ToSections(Sections& sections, const OuterType outer_type, const
     switch (m_type) {
     case Type::ELISION: {
         // If the inner result is empty, use three dots for elision
-        sections.PushSection({indent_next + "...", m_description});
+        sections.PushSection({indent + "..." + maybe_separator, m_description});
         return;
     }
     case Type::NONE: {
-        sections.PushSection({indent + "None", Description("json null")});
+        sections.PushSection({indent + "null" + maybe_separator, Description("json null")});
         return;
     }
     case Type::STR: {
@@ -643,10 +643,10 @@ void RPCResult::ToSections(Sections& sections, const OuterType outer_type, const
         for (const auto& i : m_inner) {
             i.ToSections(sections, OuterType::ARR, current_indent + 2);
         }
-        if (m_type == Type::ARR) {
+        CHECK_NONFATAL(!m_inner.empty());
+        if (m_type == Type::ARR && m_inner.back().m_type != Type::ELISION) {
             sections.PushSection({indent_next + "...", ""});
         } else {
-            CHECK_NONFATAL(!m_inner.empty());
             // Remove final comma, which would be invalid JSON
             sections.m_sections.back().m_left.pop_back();
         }
@@ -659,11 +659,11 @@ void RPCResult::ToSections(Sections& sections, const OuterType outer_type, const
         for (const auto& i : m_inner) {
             i.ToSections(sections, OuterType::OBJ, current_indent + 2);
         }
-        if (m_type == Type::OBJ_DYN) {
+        CHECK_NONFATAL(!m_inner.empty());
+        if (m_type == Type::OBJ_DYN && m_inner.back().m_type != Type::ELISION) {
             // If the dictionary keys are dynamic, use three dots for continuation
             sections.PushSection({indent_next + "...", ""});
         } else {
-            CHECK_NONFATAL(!m_inner.empty());
             // Remove final comma, which would be invalid JSON
             sections.m_sections.back().m_left.pop_back();
         }