docs: update documentation

Author: TendTo

CHANGELOG.md

@@ -11,7 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - `Doxyfile` is now included in the `doxygen` rule DefaultInfo provider
 - Mnemonic `DoxygenBuild` added to the `ctx.run` in the `doxygen` rule
-- Added support by default for the `$(OUTDIR)` make variable in the `doxygen` rule
+- Added support by default for the `$(OUTDIR)` make variable in the `doxygen` rule [#28](https://github.com/TendTo/rules_doxygen/pull/28) (thanks to @kaycebasques)
 - `doxylink` example in the documentation
 
 ### Changed

docs/doxygen_doc.md

@@ -118,7 +118,7 @@ By default, the following make variables are available:
 - `$(OUTDIR)`: The output directory where the documentation will be generated.
 - All the predefined variables indicated in the [Bazel documentation](https://bazel.build/reference/be/make-variables#predefined_variables).
 
-The former is particularly useful when `doxygen` needs to generate unusual files, such as tag files.
+The former is particularly useful when `doxygen` needs to generate unusual files, such as [tag files](https://www.doxygen.nl/manual/config.html#cfg_generate_tagfile).
 For example, you can use it to generate a tag file in the output directory:
 
 ```bzl

doxygen/doxygen.bzl

@@ -513,7 +513,7 @@ def doxygen(
     - `$(OUTDIR)`: The output directory where the documentation will be generated.
     - All the predefined variables indicated in the [Bazel documentation](https://bazel.build/reference/be/make-variables#predefined_variables).
 
-    The former is particularly useful when `doxygen` needs to generate unusual files, such as tag files.
+    The former is particularly useful when `doxygen` needs to generate unusual files, such as [tag files](https://www.doxygen.nl/manual/config.html#cfg_generate_tagfile).
     For example, you can use it to generate a tag file in the output directory:
 
     ```bzl