cpp: docs: Fix doc generating from poppler-version.h.in
Doxygen generated document did not contain
`poppler::version_string()`, `poppler::version_major()`,
`poppler::version_minor()`, and `poppler::version_micro()`.
These descriptions are written in `poppler-version.h.in`
in source files and doxygen could not parse `poppler-version.h.in`
because its extension is not mapped to any languages.
This commit adds `*.in` to C++ in extension mapping.
As a result, doxygen parses `poppler-version.h.in` as C++ file.
So generated document becomes to contain
`poppler::version_string()` etc.
diff --git a/cpp/Doxyfile b/cpp/Doxyfile
index 0b36e36..0c3244b 100644
--- a/cpp/Doxyfile
+++ b/cpp/Doxyfile
@@ -217,7 +217,7 @@
# (default is Fortran), use: inc=Fortran f=C. Note that for custom extensions
# you also need to set FILE_PATTERNS otherwise the files are not read by doxygen.
-EXTENSION_MAPPING =
+EXTENSION_MAPPING = in=C++
# If you use STL classes (i.e. std::string, std::vector, etc.) but do not want
# to include (a tag file for) the STL sources as input, then you should
