Add support for xmllint (#251)

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Co-authored-by: Radon Rosborough <radon@intuitiveexplanations.com>

CHANGELOG.md

@@ -63,13 +63,6 @@ The format is based on [Keep a Changelog].
 
 ### Formatters
 
-* [`yq`](https://mikefarah.gitbook.io/yq/) for YAML, JSON, CSV, TSV, XML and [.properties](https://en.wikipedia.org/wiki/.properties) ([#250]).
-* [purs-tidy](https://github.com/natefaubion/purescript-tidy) for PureScript ([#182]).
-* [`jq`](https://stedolan.github.io/jq/) for
-  [JSON](https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Objects/JSON)
-  ([#174]).
-* [`gawk`](https://www.gnu.org/software/gawk/) for
-  [awk](https://en.wikipedia.org/wiki/AWK) ([#187]).
 * [`asmfmt`](https://github.com/klauspost/asmfmt) for assembly ([#168]).
 * [`astyle`](https://github.com/steinwurf/astyle) for C ([#169]).
 * [`beautysh`](https://github.com/lovesegfault/beautysh) for shell
@@ -79,10 +72,17 @@ The format is based on [Keep a Changelog].
 * [`cmake-format`](https://github.com/cheshirekow/cmake_format)
   for [CMake](https://cmake.org/) ([#172]).
 * [`fourmolu`](https://github.com/fourmolu/fourmolu) for haskell
+* [`gawk`](https://www.gnu.org/software/gawk/) for
+  [awk](https://en.wikipedia.org/wiki/AWK) ([#187]).
+* [`hclfmt`](https://github.com/hashicorp/hcl/tree/main/cmd/hclfmt) for [HCL](https://github.com/hashicorp/hcl) ([#231])
 * [`html-tidy`](https://www.html-tidy.org/) for HTML/XML ([#173]).
+* [`jq`](https://stedolan.github.io/jq/) for
+  [JSON](https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Objects/JSON)
+  ([#174]).
 * [`ormolu`](https://github.com/tweag/ormolu) for haskell.
 * [`perltidy`](https://perltidy.sourceforge.net/) for
   [perl](https://www.perl.org/) ([#175]).
+* [purs-tidy](https://github.com/natefaubion/purescript-tidy) for PureScript ([#182]).
 * [`rubocop`](https://github.com/rubocop/rubocop) for [ruby](https://www.ruby-lang.org/en/) ([#176]).
 * [`ruby-standard`](https://github.com/standardrb/standard) for
   [ruby](https://www.ruby-lang.org/en/) ([#201])
@@ -90,8 +90,9 @@ The format is based on [Keep a Changelog].
   [python](https://python.org) ([#236])
 * [`rufo`](https://github.com/ruby-formatter/rufo) for
   [Ruby](https://www.ruby-lang.org/en/) ([#177]).
+* [`xmllint`](https://gitlab.gnome.org/GNOME/libxml2) for XML ([#251]).
 * [`yapf`](https://github.com/google/yapf) for [Python](https://www.python.org/) ([#196])
-* [`hclfmt`](https://github.com/hashicorp/hcl/tree/main/cmd/hclfmt) for [HCL](https://github.com/hashicorp/hcl) ([#231])
+* [`yq`](https://mikefarah.gitbook.io/yq/) for YAML, JSON, CSV, TSV, XML and [.properties](https://en.wikipedia.org/wiki/.properties) ([#250]).
 
 [#167]: https://github.com/radian-software/apheleia/pull/167
 [#168]: https://github.com/radian-software/apheleia/pull/168

apheleia-formatters.el

@@ -149,6 +149,7 @@
     (stylua . ("stylua" "-"))
     (rustfmt . ("rustfmt" "--quiet" "--emit" "stdout"))
     (terraform . ("terraform" "fmt" "-"))
+    (xmllint . ("xmllint" "--format" "-"))
     (yapf . ("yapf"))
     (yq-csv . ("yq" "--prettyPrint" "--no-colors"
                "--input-format" "csv" "--output-format" "csv"))

test/formatters/installers/xmllint.bash

@@ -0,0 +1 @@
+apt-get install -y libxml2-utils

test/formatters/samplecode/xmllint/in.xml

@@ -0,0 +1 @@
+<hello  who='world'  />

test/formatters/samplecode/xmllint/out.xml

@@ -0,0 +1,2 @@
+<?xml version="1.0"?>
+<hello who="world"/>