cmDocumentationEntry: Drop all user provided ctors for C++ >= 14

There is no need for them cuz:

- the last field has a default value
- all static instances use 2 arguments convertible to `std::string`
- "dynamic" instances used for _Generator_ doc entries access
  fields diectly using default constructed instance

Moreover, compiler may generate move ctor/assign when needed.

1 files changed, 3 insertions, 2 deletions

diff --git a/Source/cmDocumentation.cxx b/Source/cmDocumentation.cxx
index e626f7e..77c5295 100644
--- a/Source/cmDocumentation.cxx
+++ b/Source/cmDocumentation.cxx
@@ -47,11 +47,12 @@ const cmDocumentationEntry cmDocumentationStandardOptions[20] = {
 };
 
 const cmDocumentationEntry cmDocumentationCPackGeneratorsHeader = {
-  nullptr, "The following generators are available on this platform:"
+  {},
+  "The following generators are available on this platform:"
 };
 
 const cmDocumentationEntry cmDocumentationCMakeGeneratorsHeader = {
-  nullptr,
+  {},
   "The following generators are available on this platform (* marks "
   "default):"
 };