Modified .bashrc to better handle Windows executables

Added a command_not_found_handle() function which will
launch Windows executables from WSL even if the .exe
extension is omitted.

Code copied from microsoft/WSL#2003

.bashrc

@@ -115,3 +115,23 @@ if ! shopt -oq posix; then
     . /etc/bash_completion
   fi
 fi
+
+# invoke windows executables and built-in commands by typing only
+# the command name WITHOUT the .exe normally required
+# based on discussion in https://github.com/Microsoft/WSL/issues/2003
+command_not_found_handle() {
+    if cmd.exe /c "(where $1 || (help $1 |findstr /V Try)) >nul 2>nul && ($* || exit 0)"; then
+        return $?
+    else
+        if [ -x /usr/lib/command-not-found ]; then
+           /usr/lib/command-not-found -- "$1"
+           return $?
+        elif [ -x /usr/share/command-not-found/command-not-found ]; then
+           /usr/share/command-not-found/command-not-found -- "$1"
+           return $?
+        else
+           printf "%s: command not found\n" "$1" >&2
+           return 127
+        fi
+    fi
+}