Indentation Rules.tmPreferences

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
	<dict>
		<key>name</key>
		<string>Indentation Rules</string>
		<key>scope</key>
		<string>text.tex, sources.bib</string>
		<key>settings</key>
		<dict>
			<key>decreaseIndentPattern</key>
			<string>(?x)
				^\s*\\end\{[^\{\}]+\}.*$
			|	^\s*\\\].*$
			|	^\s*\}.*
			|	^\s*\%.*\(end\).*$
			</string>
			<key>increaseIndentPattern</key>
			<string>(?x)
				^\s*\\begin\{(?!document)[^\{\}]+\}(\{.*\}|\[.*\])*$
			|	^.*\\\[\s*$
			|	^.*\\(.+)\{$
			</string>
		</dict>
		<key>uuid</key>
		<string>02EB44C6-9203-4F4C-BFCB-7E3360B12842</string>
	</dict>
</plist>

Changes from albertxing's original:

• removed rule to indent sections and subsections
• changed \begin{} indentation rule to indent everything except \begin{document}