Bug 1446097. Switch to "set" as the canonical nsGkAtoms name of the string "set", so it matches the actual tag name "set" in SVG. r=hsivonen,njn

Most of the noise is from the fact that clang-format on parser/html/*.{h,cpp}
reformatted all sorts of stuff.  Not running it caused lots of format changes
from the generator... I guess we changed the format rules since the last time
this got run?

MozReview-Commit-ID: IA2G87zUIKN

parser/html/nsHtml5AtomTable.cpp

@@ -31,9 +31,7 @@ nsHtml5AtomTable::nsHtml5AtomTable()
 #endif
 }
 
-nsHtml5AtomTable::~nsHtml5AtomTable()
-{
-}
+nsHtml5AtomTable::~nsHtml5AtomTable() {}
 
 nsAtom*
 nsHtml5AtomTable::GetAtom(const nsAString& aKey)