docs: replace sed with nodejs-based md patch

https://superuser.com/questions/112834/how-to-match-whitespace-in-sed
https://stackoverflow.com/questions/18840175/find-and-replace-with-spaces-using-sed-mac-terminal

.travis.yml

@@ -25,8 +25,6 @@ install:
 script:
   # verify readme has been generated
   - npm run readme
-  # show diff for debugging
-  - git diff
   - test -z "$(git diff)"
 
   # run tests with coverage

package.json

@@ -39,7 +39,7 @@
     "posttest": "npm run lint -s",
     "lint": "eslint . --cache",
     "cover": "nyc npm test -s",
-    "readme": "jsdoc2md --template readme.hbs index.js | sed  's/[[:space:]]+$//g;s/**\\(Returns\\|Throws\\|Params\\|Properties\\)/<br>**\\1/g' > readme.md"
+    "readme": "jsdoc2md --template readme.hbs index.js | node patch-md.js > readme.md"
   },
   "devDependencies": {
     "ava": "^4.2.0",

patch-md.js

@@ -0,0 +1,24 @@
+#!/usr/bin/env node
+'use strict';
+
+let buff = '';
+process.stdin
+  .on('data', (data) => {
+    buff += data;
+  })
+  .on('end', () => {
+    if (buff.length > 0) {
+      buff.trim().split(/\r\n|\n/).forEach(processLine);
+    }
+  });
+
+function processLine(line) {
+  process.stdout.write(patchLine(line) + '\n');
+}
+
+function patchLine(line) {
+  if (line.startsWith('**')) {
+    return line.replace(/\s+$/, '<br/>');
+  }
+  return line;
+}

readme.md

@@ -50,7 +50,7 @@ get('http://google.com')
 Retry module setup function. Takes an options object that configures the
 default retry options.
 
-**Kind**: global function  
+**Kind**: global function<br/>
 **Returns**: <code>function</code> - [retryWrapper](retryWrapper) A decorator function that wraps a
   a function to turn it into a retry-enabled function.  
 **Throws**:
@@ -71,8 +71,8 @@ to retry.
 retryify function decorator. Allows configuration on a function by function
 basis.
 
-**Kind**: inner method of [<code>retryify</code>](#retryify)  
-**Returns**: <code>function</code> - The wrapped function.  
+**Kind**: inner method of [<code>retryify</code>](#retryify)<br/>
+**Returns**: <code>function</code> - The wrapped function.<br/>
 
 | Param | Type | Description |
 | --- | --- | --- |
@@ -82,7 +82,7 @@ basis.
 <a name="Options"></a>
 
 ## Options : <code>Object</code>
-**Kind**: global typedef  
+**Kind**: global typedef<br/>
 **Properties**
 
 | Name | Type | Default | Description |