Use correct LIB escaping for LD_PRELOAD

This ensures we use the architecture independent path in the environment
variable, allowing multiarch + multilib system paths to be respected.

Signed-off-by: Ikey Doherty <ikey@solus-project.com>

README.md

@@ -64,11 +64,11 @@ sudo ninja install
 
 After installing `libgamemodeauto.so` simple preload it into the program. Examples:
 ```bash
-LD_PRELOAD=/usr/lib/libgamemodeauto.so ./game
+LD_PRELOAD=/usr/\$LIB/libgamemodeauto.so ./game
 ```
 Or steam launch options
 ```bash
-LD_PRELOAD=/usr/lib/libgamemodeauto.so %command%
+LD_PRELOAD=/usr/\$LIB/libgamemodeauto.so %command%
 ```
 
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