Fix typos in clang

Found via codespell -q 3 -I ../clang-whitelist.txt
Where whitelist consists of:

  archtype
  cas
  classs
  checkk
  compres
  definit
  frome
  iff
  inteval
  ith
  lod
  methode
  nd
  optin
  ot
  pres
  statics
  te
  thru

Patch by luzpaz! (This is a subset of D44188 that applies cleanly with a few
files that have dubious fixes reverted.)

Differential revision: https://reviews.llvm.org/D44188

llvm-svn: 329399
diff --git a/clang/lib/Tooling/FileMatchTrie.cpp b/clang/lib/Tooling/FileMatchTrie.cpp
index 248d4e2..3e7c70e 100644
--- a/clang/lib/Tooling/FileMatchTrie.cpp
+++ b/clang/lib/Tooling/FileMatchTrie.cpp
@@ -91,7 +91,7 @@
   ///
   /// To find the best matching node for a given path 'p', the
   /// \c findEquivalent() function is called recursively for each path segment
-  /// (back to fron) of 'p' until a node 'n' is reached that does not ..
+  /// (back to front) of 'p' until a node 'n' is reached that does not ..
   /// - .. have children. In this case it is checked
   ///   whether the stored path is equivalent to 'p'. If yes, the best match is
   ///   found. Otherwise continue with the parent node as if this node did not