This fixes the plugin ABI break that happened in previous commmit.

Closes #1134

Say hello to Geany 1.29 "Jowar"!

Windows installer: C and GTK runtime installation

Don't require plugin key group name and label strings to be static

Take a copy of the strings not to require them to live live as long as
the plugin does.

This is mostly useful for plugins implemented in dynamic languages
(e.g. through a plugin proxy), as most C plugins will use a static
string here; but it makes the API more straightforward and avoids odd
issues if any plugin doesn't use static strings here, even C ones.

Closes #1125.

For example "doc/doxygen_sqlite3.db" is created on Windows/MSYS2.

The location of the file changed since we are using MSYS2.

Update of Slovak translation

While the installation of the GTK runtime environment is optional,
we need the C runtime environment in every case and so install
it unconditionally.

Fix fuzzy entries in German translation

Update zh_CN translation

Fixes #1102.

updated it.po for upcoming 1.28

Properly expose TMTag which already contains documented members.