Squashed 'src/minisketch/' changes from d1e6bb8bbf..ea8f66b1ea

ea8f66b1ea Merge sipa/minisketch#89: header: Delete default Minisketch constructor
fc24958646 Merge sipa/minisketch#94: misc: trim trailing whitespace
485b16e7ff misc: trim trailing whitespace
5cc7d20866 header: Delete default Minisketch constructor

git-subtree-dir: src/minisketch
git-subtree-split: ea8f66b1eabb0388d221daaa4706120a5083da0c

include/minisketch.h

@@ -248,8 +248,8 @@ public:
     /** Check whether this Minisketch object is valid. */
     explicit operator bool() const noexcept { return bool{m_minisketch}; }
 
-    /** Construct an (invalid) Minisketch object. */
+    /** Default constructor is deleted. */
-    Minisketch() noexcept = default;
+    Minisketch() noexcept = delete;
 
     /** Move constructor. */
     Minisketch(Minisketch&&) noexcept = default;