docs: Fix broken fg(1) links

doc/api/readline.md

@@ -124,7 +124,7 @@ added: v0.7.5
 
 The `'SIGCONT'` event is emitted when a Node.js process previously moved into
 the background using `<ctrl>-Z` (i.e. `SIGTSTP`) is then brought back to the
-foreground using fg(1).
+foreground using fg(1p).
 
 If the `input` stream was paused *before* the `SIGTSTP` request, this event will
 not be emitted.
@@ -174,7 +174,7 @@ input, typically known as `SIGTSTP`. If there are no `SIGTSTP` event listeners
 registered when the `input` stream receives a `SIGTSTP`, the Node.js process
 will be sent to the background.
 
-When the program is resumed using fg(1), the `'pause'` and `SIGCONT` events
+When the program is resumed using fg(1p), the `'pause'` and `SIGCONT` events
 will be emitted. These can be used to resume the `input` stream.
 
 The `'pause'` and `'SIGCONT'` events will not be emitted if the `input` was

test/doctool/test-doctool-html.js

@@ -48,13 +48,15 @@ const testData = [
       '<h2>Foobar II<span><a class="mark" href="#foo_foobar_ii" ' +
       'id="foo_foobar_ii">#</a></span></h2>' +
       '<div class="api_metadata"><span>Added in: v5.3.0, v4.2.0</span></div> ' +
-      '<p>Describe <code>Foobar II</code> in more detail here.</p>' +
+      '<p>Describe <code>Foobar II</code> in more detail here.' +
+      '<a href="http://man7.org/linux/man-pages/man1/fg.1.html">fg(1)</a></p>' +
       '<h2>Deprecated thingy<span><a class="mark" ' +
       'href="#foo_deprecated_thingy" id="foo_deprecated_thingy">#</a>' +
       '</span></h2>' +
       '<div class="api_metadata"><span>Added in: v1.0.0</span>' +
       '<span>Deprecated since: v2.0.0</span></div><p>Describe ' +
-      '<code>Deprecated thingy</code> in more detail here.</p>' +
+      '<code>Deprecated thingy</code> in more detail here.' +
+      '<a href="http://man7.org/linux/man-pages/man1/fg.1p.html">fg(1p)</a></p>' +
       '<h2>Something<span><a class="mark" href="#foo_something" ' +
       'id="foo_something">#</a></span></h2> ' +
       '<!-- This is not a metadata comment --> ' +

test/fixtures/doc_with_yaml.md

@@ -14,15 +14,15 @@ added:
   - v4.2.0
 -->
 
-Describe `Foobar II` in more detail here.
+Describe `Foobar II` in more detail here. fg(1)
 
 ## Deprecated thingy
 <!-- YAML
 added: v1.0.0
 deprecated: v2.0.0
 -->
 
-Describe `Deprecated thingy` in more detail here.
+Describe `Deprecated thingy` in more detail here. fg(1p)
 
 ## Something
 <!-- This is not a metadata comment -->

tools/doc/html.js

@@ -288,17 +288,19 @@ var BSD_ONLY_SYSCALLS = new Set(['lchmod']);
 // Returns modified text, with such refs replace with HTML links, for example
 // '<a href="http://man7.org/linux/man-pages/man2/open.2.html">open(2)</a>'
 function linkManPages(text) {
-  return text.replace(/ ([a-z.]+)\((\d)\)/gm, function(match, name, number) {
-    // name consists of lowercase letters, number is a single digit
-    var displayAs = name + '(' + number + ')';
-    if (BSD_ONLY_SYSCALLS.has(name)) {
-      return ' <a href="https://www.freebsd.org/cgi/man.cgi?query=' + name +
-             '&sektion=' + number + '">' + displayAs + '</a>';
-    } else {
-      return ' <a href="http://man7.org/linux/man-pages/man' + number +
-             '/' + name + '.' + number + '.html">' + displayAs + '</a>';
-    }
-  });
+  return text.replace(
+    / ([a-z.]+)\((\d)([a-z]?)\)/gm,
+    (match, name, number, optionalCharacter) => {
+      // name consists of lowercase letters, number is a single digit
+      var displayAs = `${name}(${number}${optionalCharacter})`;
+      if (BSD_ONLY_SYSCALLS.has(name)) {
+        return ` <a href="https://www.freebsd.org/cgi/man.cgi?query=${name}` +
+          `&sektion=${number}">${displayAs}</a>`;
+      } else {
+        return ` <a href="http://man7.org/linux/man-pages/man${number}` +
+          `/${name}.${number}${optionalCharacter}.html">${displayAs}</a>`;
+      }
+    });
 }
 
 function linkJsTypeDocs(text) {