L5X export: root element tag uses wrong casing (Rslogix5000Content vs RSLogix5000Content)

[cmwarre]

Description

The root XML element generated by to_xml() uses incorrect casing:

<!-- Generated -->
<Rslogix5000Content ...>

<!-- Expected (matches Studio 5000 / Logix Designer export) -->
<RSLogix5000Content ...>

Impact

Tools that consume L5X files (including Studio 5000 import and third-party tooling) validate the root element name. The wrong casing will likely cause import failures.

Steps to Reproduce

from acd.api import ExportL5x
exporter = ExportL5x("project.ACD", "build/")
xml = exporter.project.to_xml()
# First non-declaration line starts with <Rslogix5000Content

Expected Behavior

Root element should be RSLogix5000Content to match the L5X schema.

[jpect]

Fixed in commit fb79240 on the jpect/acd fork. A follow-up PR will be submitted once the initial PR #18 is reviewed.