Add opinionated .markdownlint.json from markdownlint-cli2 project, re…

…flow README.md.

.markdownlint.json

@@ -0,0 +1,49 @@
+{
+  "code-block-style": {
+    "style": "fenced"
+  },
+  "code-fence-style": {
+    "style": "backtick"
+  },
+  "emphasis-style": {
+    "style": "asterisk"
+  },
+  "fenced-code-language": {
+    "allowed_languages": [
+      "yaml"
+    ],
+    "language_only": true
+  },
+  "heading-style": {
+    "style": "atx"
+  },
+  "hr-style": {
+    "style": "---"
+  },
+  "line-length": {
+    "strict": true,
+    "code_blocks": false
+  },
+  "no-duplicate-heading": {
+    "siblings_only": true
+  },
+  "ol-prefix": {
+    "style": "ordered"
+  },
+  "proper-names": {
+    "code_blocks": false,
+    "names": [
+      "CommonMark",
+      "JavaScript",
+      "Markdown",
+      "markdownlint",
+      "markdownlint-cli2"
+    ]
+  },
+  "strong-style": {
+    "style": "asterisk"
+  },
+  "ul-style": {
+    "style": "dash"
+  }
+}

README.md

@@ -1,11 +1,11 @@
 # markdownlint-cli2-action
 
-> A GitHub Action to run the [`markdownlint-cli2`][markdownlint-cli2] tool
-for linting [Markdown][markdown]/[CommonMark][commonmark] files with
+> A GitHub Action to run the [`markdownlint-cli2`][markdownlint-cli2] tool for
+linting [Markdown][markdown]/[CommonMark][commonmark] files with
 [`markdownlint`][markdownlint]
 
-`markdownlint-cli2` has extensive support for configuring options and
-disabling or customizing `markdownlint` rules. See the
+`markdownlint-cli2` has extensive support for configuring options and disabling
+or customizing `markdownlint` rules. See the
 [`markdownlint-cli2` README][markdownlint-cli2] for more information.
 `markdownlint` includes a wide variety of rules for analyzing and improving
 Markdown content. See the [`markdownlint` README][markdownlint] for more
@@ -19,20 +19,20 @@ Command to run (unset, `fix`, or `config`)
 
 If unspecified or `""`, the `markdownlint-cli2` command is run.
 
-If set to `fix`, the `markdownlint-cli2-fix` command is run and supported
-issues will be fixed automatically.
+If set to `fix`, the `markdownlint-cli2-fix` command is run and supported issues
+will be fixed automatically.
 
-If set to `config`, the `markdownlint-cli2-config` command is run and the
-first element of `globs` should specify a supported configuration file.
+If set to `config`, the `markdownlint-cli2-config` command is run and the first
+element of `globs` should specify a supported configuration file.
 
 For more detail: [documentation for `markdownlint-cli2`][command-line].
 
 ### globs (optional)
 
 Glob expression(s) of files to lint (newline-delimited by default)
 
-The default `*.{md,markdown}` lints all Markdown files in the base directory
-of a project.
+The default `*.{md,markdown}` lints all Markdown files in the base directory of
+a project.
 
 For more detail: [glob syntax in `markdownlint-cli2`][glob-syntax].
 
@@ -114,8 +114,8 @@ See [`example.yml`][example-yml] for a simple GitHub workflow that uses
 `markdownlint-cli2-action`.
 
 See [`changed.yml`][changed-yml] for a GitHub workflow that lints only the
-Markdown files that changed in the most recent commit (useful for Pull
-Requests and/or gradually introducing linting rules to a new repository).
+Markdown files that changed in the most recent commit (useful for Pull Requests
+and/or gradually introducing linting rules to a new repository).
 
 [changed-yml]: .github/workflows/changed.yml
 [command-line]: https://github.com/DavidAnson/markdownlint-cli2#command-line