DevTools: Add JSDoc for static methods, fix JSDoc types and induced errors

Source/devtools/front_end/sdk/OverridesSupport.js

Index: Source/devtools/front_end/sdk/OverridesSupport.js
diff --git a/Source/devtools/front_end/sdk/OverridesSupport.js b/Source/devtools/front_end/sdk/OverridesSupport.js
index 98b36915c03f2e5f10fcb7e4232649e30ad127c7..55a850ce0b8229fce558f8bcdfe83ebdb692a5a2 100644
--- a/Source/devtools/front_end/sdk/OverridesSupport.js
+++ b/Source/devtools/front_end/sdk/OverridesSupport.js
@@ -260,7 +260,7 @@ WebInspector.OverridesSupport.DeviceOrientation.clearDeviceOrientationOverride =
 
 /**
  * @param {string} value
- * @return {!string}
+ * @return {string}
  */
 WebInspector.OverridesSupport.integerInputValidator = function(value)
 {
@@ -271,7 +271,7 @@ WebInspector.OverridesSupport.integerInputValidator = function(value)
 
 /**
  * @param {string} value
- * @return {!string}
+ * @return {string}
  */
 WebInspector.OverridesSupport.doubleInputValidator = function(value)
 {
@@ -282,7 +282,7 @@ WebInspector.OverridesSupport.doubleInputValidator = function(value)
 
 /**
  * @param {string} value
- * @return {!string}
+ * @return {string}
  */
 WebInspector.OverridesSupport.networkDomainsValidator = function(value)
 {