[LLDB] Improve documentation for ~/.lldbinit

The content of the ~/.lldbinit file as described in lldbinit.md was
confusing and led multiple people to include the chevrons in the path
to chromium/src/tools/lldb. Chevrons SHOULD NOT BE INCLUDED.

Hopefully this CL makes this a bit clearer.

Bug: N/A
Change-Id: I4e814c4fd3f29d7029f61370a0f38a030ccae9a2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3597559
Reviewed-by: Erik Chen <erikchen@chromium.org>
Commit-Queue: Benjamin Beaudry <benjamin.beaudry@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#994463}

docs/lldbinit.md

@@ -8,7 +8,7 @@ To use, add the following to your `~/.lldbinit`
 
 ```
 # So that lldbinit.py takes precedence.
-script sys.path[:0] = ['<.../path/to/chromium/src/tools/lldb>']
+script sys.path[:0] = ['/<your-path>/chromium/src/tools/lldb']
 script import lldbinit
 ```