docs: Enable Syntax Highlighting for Code Snippits

tests/README.md

@@ -38,17 +38,19 @@ computes `$region_highlight`), but will not affect subsequent tests.  The
 current working directory of tests is set to a newly-created empty directory,
 which is automatically cleaned up after the test exits. For example:
 
-    setopt PATH_DIRS
-    mkdir -p foo/bar
-    touch foo/bar/testing-issue-228
-    chmod  +x foo/bar/testing-issue-228
-    path+=( "$PWD"/foo )
+```zsh
+setopt PATH_DIRS
+mkdir -p foo/bar
+touch foo/bar/testing-issue-228
+chmod  +x foo/bar/testing-issue-228
+path+=( "$PWD"/foo )
 
-    BUFFER='bar/testing-issue-228'
+BUFFER='bar/testing-issue-228'
 
-    expected_region_highlight=(
-      "1 21 command" # bar/testing-issue-228
-    )
+expected_region_highlight=(
+  "1 21 command" # bar/testing-issue-228
+)
+```
 
 
 Writing new tests
@@ -56,7 +58,9 @@ Writing new tests
 
 An experimental tool is available to generate test files:
 
-    zsh -f tests/generate.zsh 'ls -x' acme newfile
+```zsh
+zsh -f tests/generate.zsh 'ls -x' acme newfile
+```
 
 This generates a `highlighters/acme/test-data/newfile.zsh` test file based on
 the current highlighting of the given `$BUFFER` (in this case, `ls -x`).
@@ -71,11 +75,15 @@ Highlighting test
 [`test-highlighting.zsh`](tests/test-highlighting.zsh) tests the correctness of
 the highlighting. Usage:
 
-    zsh test-highlighting.zsh <HIGHLIGHTER NAME>
+```zsh
+zsh test-highlighting.zsh <HIGHLIGHTER NAME>
+```
 
 All tests may be run with
 
-    make test
+```zsh
+make test
+```
 
 which will run all highlighting tests and report results in [TAP format][TAP].
 By default, the results of all tests will be printed; to show only "interesting"
@@ -91,8 +99,12 @@ Performance test
 [`test-perfs.zsh`](tests/test-perfs.zsh) measures the time spent doing the
 highlighting. Usage:
 
-    zsh test-perfs.zsh <HIGHLIGHTER NAME>
+```zsh
+zsh test-perfs.zsh <HIGHLIGHTER NAME>
+```
 
 All tests may be run with
 
-    make perf
+```zsh
+make perf
+```