Allow the docs not to just be in a folder called docs

Also:
- regex escaping
- update api documentation

lib/server/readMetadata.js

@@ -13,6 +13,7 @@ const glob = require("glob");
 const chalk = require("chalk");
 const siteConfig = require(CWD + "/siteConfig.js");
 const versionFallback = require("./versionFallback.js");
+const escapeStringRegexp = require("escape-string-regexp");
 
 const ENABLE_VERSIONING = fs.existsSync(CWD + "/versions.json");
 
@@ -31,13 +32,15 @@ if (fs.existsSync(CWD + "/languages.js")) {
   ];
 }
 
-// Can add additional path information to the docs folder
+// Can have a custom docs path. Top level folder still needs to be in directory
+// at the same level as `website`, not inside `website`.
 //   e.g., docs/whereDocsReallyExist
+//         website-docs/
 // All .md docs still (currently) must be in one flat directory hierarchy.
 //   e.g., docs/whereDocsReallyExist/*.md (all .md files in this dir)
 function getDocsPath() {
-  return siteConfig.docsAdditionalPath
-    ? "docs" + siteConfig.docsAdditionalPath
+  return siteConfig.customDocsPath
+    ? siteConfig.customDocsPath
     : "docs";
 }
 // returns map from id to object containing sidebar ordering info
@@ -125,7 +128,7 @@ function extractMetadata(content) {
 function processMetadata(file) {
   const result = extractMetadata(fs.readFileSync(file, "utf8"));
 
-  let regexSubFolder = new RegExp("/" + getDocsPath() + "\/(.*)\/.*/");
+  let regexSubFolder = new RegExp("/" + escapeStringRegexp(getDocsPath()) + "\/(.*)\/.*/");
 
   let language = "en";
   const match = regexSubFolder.exec(file);