Fix documentation section references
Fix documentation section references

Fix ID collision between two sections which were both trying to call
themselves "TotemPlParser". This stops the irritating stream of warnings from
gtk-doc when building.

MathieuDuponchelle/totem-pl-parser,MathieuDuponchelle/totem-pl-parser,MathieuDuponchelle/totem-pl-parser,pwithnall/totem-pl-parser,MathieuDuponchelle/totem-pl-parser,pwithnall/totem-pl-parser