Update READMEs to be more obvious about XML lexers.

README.md

@@ -207,14 +207,13 @@ for details on implementing lexers. Most concepts apply directly to Chroma,
 but see existing lexer implementations for real examples.
 
 In many cases lexers can be automatically converted directly from Pygments by
-using the included Python 3 script `pygments2chroma.py`. I use something like
+using the included Python 3 script `pygments2chroma_xml.py`. I use something like
 the following:
 
 ```sh
-python3 _tools/pygments2chroma.py \
+python3 _tools/pygments2chroma_xml.py \
   pygments.lexers.jvm.KotlinLexer \
-  > lexers/k/kotlin.go \
-  && gofmt -s -w lexers/k/kotlin.go
+  > lexers/embedded/kotlin.xml
 ```
 
 See notes in [pygments-lexers.txt](https://github.com/alecthomas/chroma/blob/master/pygments-lexers.txt)

lexers/README.md

@@ -1,19 +1,24 @@
-# Lexer tests
+# Chroma lexers
+
+All lexers in Chroma should now be defined in XML unless they require custom code.
+
+## Lexer tests
 
 The tests in this directory feed a known input `testdata/<name>.actual` into the parser for `<name>` and check
 that its output matches `<name>.exported`.
 
 It is also possible to perform several tests on a same parser `<name>`, by placing know inputs `*.actual` into a
 directory `testdata/<name>/`.
 
-## Running the tests
+### Running the tests
 
 Run the tests as normal:
 ```go
 go test ./lexers
 ```
 
-## Update existing tests
+### Update existing tests
+
 When you add a new test data file (`*.actual`), you need to regenerate all tests. That's how Chroma creates the `*.expected` test file based on the corresponding lexer.
 
 To regenerate all tests, type in your terminal:
@@ -26,7 +31,8 @@ This first sets the `RECORD` environment variable to `true`. Then it runs `go te
 
 (That environment variable tells Chroma it needs to output test data. After running `go test ./lexers` you can remove or reset that variable.)
 
-### Windows users
+#### Windows users
+
 Windows users will find that the `RECORD=true go test ./lexers` command fails in both the standard command prompt terminal and in PowerShell.
 
 Instead we have to perform both steps separately: