fix URL to download page.

Signed-off-by: GCer-Hidenori <[email protected]>

doc/getting-started.md

@@ -41,7 +41,7 @@ $ alias grun='java -Xmx500M -cp "/usr/local/lib/antlr-4.10.1-complete.jar:$CLASS
 (*Thanks to Graham Wideman*)
 
 0. Install Java (version 1.7 or higher)
-1. Download antlr-4.10.1-complete.jar (or whatever version) from [https://www.antlr.org/download/](https://www.antlr.org/download/)
+1. Download antlr-4.10.1-complete.jar (or whatever version) from [https://www.antlr.org/download.html](https://www.antlr.org/download.html)
 Save to your directory for 3rd party Java libraries, say `C:\Javalib`
 2. Add `antlr-4.10.1-complete.jar` to CLASSPATH, either:
   * Permanently: Using System Properties dialog > Environment variables > Create or append to `CLASSPATH` variable