[SYCL] Fix doc typos (#6667)

Signed-off-by: Sarnie, Nick <[email protected]>

Author: sarnex

sycl/doc/GetStartedGuide.md

@@ -47,7 +47,7 @@ and a wide range of compute accelerators such as GPU and FPGA.
   * Windows: `Visual Studio` version 15.7 preview 4 or later -
     [Download](https://visualstudio.microsoft.com/downloads/)
 
-Alternatively, you can use Docker image, that has everything you need for building
+Alternatively, you can use a Docker image that has everything you need for building
 pre-installed:
 
 ```