Fixup some doc and compile issues.

Change-Id: I75547e3fb4e1e4be08bde08f0bcfcf7e979791e7
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/25640
Reviewed-by: dan sinclair <dsinclair@chromium.org>

Doxyfile

@@ -986,7 +986,7 @@ FILTER_SOURCE_PATTERNS =
 # (index.html). This can be useful if you have a project on for instance GitHub
 # and want to reuse the introduction page also for the doxygen output.
 
-USE_MDFILE_AS_MAINPAGE = README.md
+USE_MDFILE_AS_MAINPAGE = ./README.md
 
 #---------------------------------------------------------------------------
 # Configuration options related to source browsing

src/reader/spirv/function.h

@@ -209,7 +209,7 @@ struct DefInfo {
   /// The SPIR-V instruction that defines the ID.
   const spvtools::opt::Instruction& inst;
   /// The position of the block that defines this ID, in the function block
-  /// order.  See method |FunctionEmitter::ComputeBlockOrderAndPositions|
+  /// order.  See method `FunctionEmitter::ComputeBlockOrderAndPositions`
   const uint32_t block_pos = 0;
 
   /// An index for uniquely and deterministically ordering all DefInfo records

src/validator_test.cc

@@ -59,7 +59,6 @@ class TypeDeterminerHelper {
       : td_(std::make_unique<TypeDeterminer>(&ctx_, &mod_)) {}
 
   TypeDeterminer* td() const { return td_.get(); }
-  ast::Module* mod() { return &mod_; }
 
  private:
   Context ctx_;