Fix build with poppler-26.01.0.

See also upstream PR https://github.com/OSGeo/gdal/pull/13664

Index: frmts/pdf/pdfio.cpp
--- frmts/pdf/pdfio.cpp.orig
+++ frmts/pdf/pdfio.cpp
@@ -252,7 +252,7 @@ int VSIPDFFileStream::lookChar()
 
 #if POPPLER_MAJOR_VERSION > 25 ||                                              \
     (POPPLER_MAJOR_VERSION == 25 && POPPLER_MINOR_VERSION >= 2)
-bool VSIPDFFileStream::reset()
+bool VSIPDFFileStream::rewind()
 #else
 void VSIPDFFileStream::reset()
 #endif
@@ -274,9 +274,9 @@ void VSIPDFFileStream::reset()
 
 #if POPPLER_MAJOR_VERSION > 25 ||                                              \
     (POPPLER_MAJOR_VERSION == 25 && POPPLER_MINOR_VERSION >= 3)
-bool VSIPDFFileStream::unfilteredReset()
+bool VSIPDFFileStream::unfilteredRewind()
 {
-    return reset();
+    return rewind();
 }
 #else
 void VSIPDFFileStream::unfilteredReset()
