Some variables in code examples were not LikeThis.

llvm-svn: 168275

llvm-svn: 168271

llvm-svn: 166821

obvious stuff and most new code being committed conforms to that.  Some old
code does not; this might cause confusion and this is the motivation to
document the correct guidelines.

llvm-svn: 166378

llvm-svn: 164964

llvm-svn: 164920

Wordsmithing by Matt Beaumont-Gay in response to r164389.

llvm-svn: 164395

llvm-svn: 164389

llvm-svn: 164311

Try not to violate conventions immediately before explaining them.

llvm-svn: 164278

llvm-svn: 164126

llvm-svn: 164101

llvm-svn: 158880

llvm-svn: 158877

llvm-svn: 158786