Updating the documentation for clang-tidy. Removes some non-ASCII characters from the documentation, and removes shell-specific single quote characters as they cause issues for some shells (such as on Windows).

llvm-svn: 243266
diff --git a/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp b/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp
index a9437a8..075df04 100644
--- a/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp
+++ b/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp
@@ -106,7 +106,7 @@
 static cl::opt<bool>
 ListChecks("list-checks",
            cl::desc("List all enabled checks and exit. Use with\n"
-                    "-checks='*' to list all available checks."),
+                    "-checks=* to list all available checks."),
            cl::init(false), cl::cat(ClangTidyCategory));
 
 static cl::opt<std::string> Config(
@@ -171,7 +171,7 @@
                    << " with check filters";
     llvm::errs() << ").\n";
     if (Stats.ErrorsIgnoredNonUserCode)
-      llvm::errs() << "Use -header-filter='.*' to display errors from all "
+      llvm::errs() << "Use -header-filter=.* to display errors from all "
                       "non-system headers.\n";
   }
 }