gnu: go-chroma: Update to 2.20.0.

* gnu/packages/golang-xyz.scm (go-chroma): Update to 2.20.0.
Do not inherit from go-github-com-alecthomas-chroma-v2 and complete
missing fields.
[arguments] <embed-files>: Copy "*.xml" files into build directory.
[native-inputs]: Remove go-github-com-alecthomas-assert-v2; add
go-github-com-alecthomas-chroma-v2.
[home-page]: Add field.
[synopsis]: Likewise.
[license]: Likewise
[description]: Add chroma CLI related description.

Change-Id: Ie3ec51ee78f96be4fee2ca1e8d3ffc5b14b9e6f0

gnu/packages/golang-xyz.scm

@@ -23842,22 +23842,38 @@ library.")
 
 (define-public go-chroma
   (package
-    (inherit go-github-com-alecthomas-chroma-v2)
     (name "go-chroma")
+    (version "2.20.0")
+    (source
+     (origin
+       (method git-fetch)
+       (uri (git-reference
+              (url "https://github.com/alecthomas/chroma")
+              (commit (string-append "v" version ))))
+       (file-name (git-file-name name version))
+       (sha256
+        (base32 "05w4hnfcxqdlsz7mkc0m3jbp1aj67wzyhq5jh8ldfgnyjnlafia3"))))
+    (build-system go-build-system)
     (arguments
      (list
       #:install-source? #f
+      #:embed-files #~(list ".*\\.xml")
       #:import-path "github.com/alecthomas/chroma/cmd/chroma"
       #:unpack-path "github.com/alecthomas/chroma"))
     (native-inputs
-     (list go-github-com-alecthomas-assert-v2
+     (list go-github-com-alecthomas-chroma-v2
            go-github-com-alecthomas-kong
            go-github-com-mattn-go-colorable
            go-github-com-mattn-go-isatty))
+    (home-page "https://github.com/alecthomas/chroma")
+    (synopsis "General purpose syntax highlighter")
     (description
-     (string-append (package-description go-github-com-alecthomas-chroma-v2)
+     "This package implements syntax highlighter for a long list of
-                    "  This package provides an command line interface (CLI)
+programming languages.  It takes source code and other structured text and
-tool."))))
+converts it into syntax highlighted HTML, ANSI-coloured text, etc.  Chroma is
+based heavily on @url{http://pygments.org/, Pygments}, and includes
+translators for Pygments lexers and styles.")
+    (license license:expat)))
 
 (define-public go-csv2table
   (package/inherit go-github-com-olekukonko-tablewriter