[feature request] disable semantic colouring by default

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### How are you using the lua-language-server?

Other

### Which OS are you using?

Windows

### What is the issue affecting?

Other

### Expected Behaviour

我在用Qt creator,昨天用lua编写插件,然后下载了Dracula / oneDark pro 两个主题插件,
结果发现lua的local function return 等关键词老是和注释一样的颜色,见下图

然后禁用主题插件之后,发现也不是主题插件导致的(默认主题下关键词也会跟注释一样颜色)
经过一天的折腾,到了晚上终于发现是lua language server 插件导致的,
一查这个插件,发现是qt 官方出品,

然后我就到qt creator论坛反馈bug, 结果发帖被判定为垃圾信息无法发帖,
然后就通过帮助菜单下找到了反馈bug的地方.

今天突然想到可能是language server导致的,就在本项目issue里搜索,发现了一个类似的issue:
https://github.com/LuaLS/lua-language-server/issues/3318
按照 tomlau10 的方法,
https://github.com/LuaLS/lua-language-server/issues/3318#issuecomment-3678348853
我在 .luarc.json 里禁用了 semantic.enable , 高亮终于正常了.
我看了一下luaLS wiki, semantic.keyword 默认关闭的,我项目也没开启, luaLS居然能影响关键词..

谁能想到一个language server居然能影响语法高亮,
谁能想到一个language server居然把关键词和注释弄成一个颜色,

所以我建议默认关闭 semantic.enable ,😭

### Actual Behaviour

.

### Reproduction steps

.

### Additional Notes

_No response_

### Log File

_No response_

Start with the semantic.enable setting and the related discussion in issue #3318, including its linked comment; .luarc.json shows the current user-level workaround. Determine where the default is established and verify that disabling it by default prevents semantic colouring from changing keyword colours while preserving the documented opt-in behavior.

Written by the indexing model from the issue text.