Fix build with poppler-26.01.0.

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

Index: frmts/pdf/pdfio.h
--- frmts/pdf/pdfio.h.orig
+++ frmts/pdf/pdfio.h
@@ -57,7 +57,7 @@ class VSIPDFFileStream final : public BaseStream
 
 #if POPPLER_MAJOR_VERSION > 25 ||                                              \
     (POPPLER_MAJOR_VERSION == 25 && POPPLER_MINOR_VERSION >= 2)
-    bool reset() override;
+    bool rewind() override;
 #else
     void reset() override;
 #endif
@@ -66,7 +66,7 @@ class VSIPDFFileStream final : public BaseStream
     {
 #if POPPLER_MAJOR_VERSION > 25 ||                                              \
     (POPPLER_MAJOR_VERSION == 25 && POPPLER_MINOR_VERSION >= 2)
-        CPL_IGNORE_RET_VAL(str->reset());
+        CPL_IGNORE_RET_VAL(str->rewind());
 #else
         str->reset();
 #endif
@@ -74,7 +74,7 @@ class VSIPDFFileStream final : public BaseStream
 
 #if POPPLER_MAJOR_VERSION > 25 ||                                              \
     (POPPLER_MAJOR_VERSION == 25 && POPPLER_MINOR_VERSION >= 3)
-    bool unfilteredReset() override;
+    bool unfilteredRewind() override;
 #else
     void unfilteredReset() override;
 #endif
