引号与句号相连时，执行会报错

[Happier-X]

当我校验如下语句时，控制台报错。

'测试'.

"测试".

“测试”.

‘测试’.

报错信息如下。

TypeError: Cannot read properties of undefined (reading 'toLowerCase')
    at file:///C:/Users/zhf52/AppData/Roaming/fnm/node-versions/v20.18.0/installation/node_modules/zhlint/lib/rules/case-abbrs.js:33:75
    at Array.filter (<anonymous>)
    at matchAbbr (file:///C:/Users/zhf52/AppData/Roaming/fnm/node-versions/v20.18.0/installation/node_modules/zhlint/lib/rules/case-abbrs.js:33:14)
    at file:///C:/Users/zhf52/AppData/Roaming/fnm/node-versions/v20.18.0/installation/node_modules/zhlint/lib/rules/case-abbrs.js:72:13
    at travel (file:///C:/Users/zhf52/AppData/Roaming/fnm/node-versions/v20.18.0/installation/node_modules/zhlint/lib/parser/travel.js:4:9)
    at file:///C:/Users/zhf52/AppData/Roaming/fnm/node-versions/v20.18.0/installation/node_modules/zhlint/lib/run.js:61:13
    at Array.forEach (<anonymous>)
    at file:///C:/Users/zhf52/AppData/Roaming/fnm/node-versions/v20.18.0/installation/node_modules/zhlint/lib/run.js:60:22
    at Array.map (<anonymous>)
    at lint (file:///C:/Users/zhf52/AppData/Roaming/fnm/node-versions/v20.18.0/installation/node_modules/zhlint/lib/run.js:51:48)