docusaurus - fix code-line-numbers: "1" not highlighting first line

This also affects docusaurus-md output. Add test, and fix filter

Author: cderv

news/changelog-1.8.md

@@ -71,6 +71,10 @@ All changes included in 1.8:
 
 - ([#12676](https://github.com/quarto-dev/quarto-cli/issues/12676)): Add support for rendering layout panels that are not floats.
 
+### `docusaurus-md`
+
+- [#13316](https://github.com/quarto-dev/quarto-cli/issues/13316): `code-line-numbers: "1"` correctly highlight the first line now.
+
 ## Projects
 
 ### `website`

src/resources/filters/quarto-pre/line-numbers.lua

@@ -27,7 +27,7 @@ function lineNumbersAttribute(el)
   local default = param(constants.kCodeLineNumbers, false)
   local lineNumbers = attribute(el, constants.kCodeLineNumbers, default)
   -- format that do accept string for this attributes. "1" and "0" should not be parsed as TRUE / FALSE
-  local acceptStrings = _quarto.format.isRevealJsOutput() and not _quarto.format.isDocusaurusOutput()
+  local acceptStrings = _quarto.format.isRevealJsOutput() or _quarto.format.isDocusaurusOutput()
   if lineNumbers == true or lineNumbers == "true" or (lineNumbers == "1" and not acceptStrings) then
     return true
   elseif lineNumbers == false or lineNumbers == "false" or lineNumbers == "0" then

tests/docs/smoke-all/2025/09/02/13316.qmd

@@ -1,4 +1,5 @@
 ---
+title: highlight first line
 format: html
 _quarto:
   tests:
@@ -10,6 +11,10 @@ _quarto:
       ensureHtmlElements:
         - ['#cb1[data-code-line-numbers="1"]', 'pre.sourceCode.number-lines']
         - []
+    docusaurus-md:
+      ensureFileRegexMatches:
+        - ['[`]{3}r \{1\} showLineNumbers']
+        - []
 execute: 
   echo: true
 ---