enabled and mitigated cppcoreguidelines-pro-type-static-cast-downcast clang-tidy warnings (#6670)

Author: firewave

.clang-tidy

@@ -19,8 +19,9 @@ Checks: >
         -openmp-*,
         -zircon-*,
         cert-err34-c,
-        google-explicit-constructor,
+        cppcoreguidelines-pro-type-static-cast-downcast,
         cppcoreguidelines-rvalue-reference-param-not-moved,
+        google-explicit-constructor,
         -bugprone-assignment-in-if-condition,
         -bugprone-branch-clone,
         -bugprone-easily-swappable-parameters,

clang-tidy.md

@@ -135,7 +135,6 @@ To be evaluated (need to remove exclusion).
 `cppcoreguidelines-avoid-const-or-ref-data-members`<br/>
 `cppcoreguidelines-macro-usage`<br/>
 `cppcoreguidelines-pro-type-member-init`<br/>
-`cppcoreguidelines-pro-type-static-cast-downcast`<br/>
 `cppcoreguidelines-prefer-member-initializer`<br/>
 `cppcoreguidelines-misleading-capture-default-by-value`<br/>
 `bugprone-argument-comment.CommentBoolLiterals`<br/>

gui/librarydialog.cpp

@@ -87,7 +87,7 @@ CppcheckLibraryData::Function *LibraryDialog::currentFunction()
     QList<QListWidgetItem *> selitems = mUi->functions->selectedItems();
     if (selitems.count() != 1)
         return nullptr;
-    return static_cast<FunctionListItem *>(selitems.first())->function;
+    return dynamic_cast<FunctionListItem *>(selitems.first())->function;
 }
 
 void LibraryDialog::openCfg()