rpc: Add option to hide RPCArg

Summary:
Also, update switch statments to our style guide

This is a backport of [[bitcoin/bitcoin#19386 | core#19386]] [4/5]
bitcoin/bitcoin@aaaaad5

Depends on D10008

Test Plan: `ninja all check-all`

Reviewers: #bitcoin_abc, majcosta

Reviewed By: #bitcoin_abc, majcosta

Differential Revision: https://reviews.bitcoinabc.org/D10009

src/rpc/util.cpp

@@ -405,9 +405,7 @@ struct Sections {
                     {indent + "]" + (outer_type != OuterType::NONE ? "," : ""),
                      ""});
                 break;
-            }
-
-                // no default case, so the compiler can warn about missing cases
+            } // no default case, so the compiler can warn about missing cases
         }
     }
 
@@ -524,6 +522,9 @@ std::string RPCHelpMan::ToString() const {
     ret += m_name;
     bool was_optional{false};
     for (const auto &arg : m_args) {
+        if (arg.m_hidden) {
+            continue;
+        }
         const bool optional = arg.IsOptional();
         ret += " ";
         if (optional) {
@@ -551,6 +552,9 @@ std::string RPCHelpMan::ToString() const {
     Sections sections;
     for (size_t i{0}; i < m_args.size(); ++i) {
         const auto &arg = m_args.at(i);
+        if (arg.m_hidden) {
+            continue;
+        }
 
         if (i == 0) {
             ret += "\nArguments:\n";
@@ -630,9 +634,7 @@ std::string RPCArg::ToDescriptionString() const {
             case Type::ARR: {
                 ret += "json array";
                 break;
-            }
-
-                // no default case, so the compiler can warn about missing cases
+            } // no default case, so the compiler can warn about missing cases
         }
     }
     if (m_fallback.which() == 1) {
@@ -651,9 +653,7 @@ std::string RPCArg::ToDescriptionString() const {
             case RPCArg::Optional::NO: {
                 ret += ", required";
                 break;
-            }
-
-                // no default case, so the compiler can warn about missing cases
+            } // no default case, so the compiler can warn about missing cases
         }
     }
     ret += ")";
@@ -762,11 +762,8 @@ void RPCResult::ToSections(Sections &sections, const OuterType outer_type,
             }
             sections.PushSection({indent + "}" + maybe_separator, ""});
             return;
-        }
-
-            // no default case, so the compiler can warn about missing cases
+        } // no default case, so the compiler can warn about missing cases
     }
-
     CHECK_NONFATAL(false);
 }
 
@@ -841,9 +838,7 @@ std::string RPCArg::ToString(const bool oneline) const {
                 res += i.ToString(oneline) + ",";
             }
             return "[" + res + "...]";
-        }
-
-            // no default case, so the compiler can warn about missing cases
+        } // no default case, so the compiler can warn about missing cases
     }
     CHECK_NONFATAL(false);
 }

src/rpc/util.h

@@ -176,6 +176,7 @@ struct RPCArg {
     //! aliases separated by | for named request arguments)
     const std::string m_names;
     const Type m_type;
+    const bool m_hidden;
     //! Only used for arrays or dicts
     const std::vector<RPCArg> m_inner;
     const Fallback m_fallback;
@@ -194,8 +195,9 @@ struct RPCArg {
     RPCArg(const std::string name, const Type type, const Fallback fallback,
            const std::string description,
            const std::string oneline_description = "",
-           const std::vector<std::string> type_str = {})
-        : m_names{std::move(name)}, m_type{std::move(type)},
+           const std::vector<std::string> type_str = {},
+           const bool hidden = false)
+        : m_names{std::move(name)}, m_type{std::move(type)}, m_hidden{hidden},
           m_fallback{std::move(fallback)}, m_description{std::move(
                                                description)},
           m_oneline_description{std::move(oneline_description)},
@@ -207,10 +209,9 @@ struct RPCArg {
            const std::string description, const std::vector<RPCArg> inner,
            const std::string oneline_description = "",
            const std::vector<std::string> type_str = {})
-        : m_names{std::move(name)}, m_type{std::move(type)}, m_inner{std::move(
-                                                                 inner)},
-          m_fallback{std::move(fallback)}, m_description{std::move(
-                                               description)},
+        : m_names{std::move(name)}, m_type{std::move(type)}, m_hidden{false},
+          m_inner{std::move(inner)}, m_fallback{std::move(fallback)},
+          m_description{std::move(description)},
           m_oneline_description{std::move(oneline_description)},
           m_type_str{std::move(type_str)} {
         CHECK_NONFATAL(type == Type::ARR || type == Type::OBJ);