Added C# Sendkeys code example (#32)

Author: alenros

docs_source_files/content/webdriver/keyboard.ja.md

@@ -49,8 +49,15 @@ driver.get("http://www.google.com")
 driver.find_element_by_name("q").send_keys("webdriver"+Keys.ENTER)
   {{< / code-panel >}}
   {{< code-panel language="csharp" >}}
-// We don't have a C# code sample yet -  Help us out and raise a PR
-  {{< / code-panel >}}
+using (var driver = new FirefoxDriver())
+{
+    // Navigate to Url
+    driver.Navigate().GoToUrl("https://google.com");
+
+    // Enter text "q" and perform keyboard action "Enter"
+    driver.FindElement(By.Name("q")).SendKeys("q" + Keys.Enter);
+}
+{{< / code-panel >}}
   {{< code-panel language="ruby" >}}
 require 'selenium-webdriver'
 driver = Selenium::WebDriver.for :firefox
@@ -106,4 +113,4 @@ class HelloSelenium {
     }
 }
   {{< / code-panel >}}
-{{< / code-tab >}}
+{{< / code-tab >}}