Update ctx path readme for module_ctx.

Closes #24890.

PiperOrigin-RevId: 721676373
Change-Id: I2ea26fb2e3215d1dfd5192183ba2d7507d817862

src/main/java/com/google/devtools/build/lib/bazel/repository/starlark/StarlarkBaseExternalContext.java

@@ -1449,10 +1449,13 @@ public String getEnvironmentValue(String name, Object defaultValue)
       name = "path",
       doc =
           """
-          Returns a path from a string, label or path. If the path is relative, it will resolve \
-          relative to the repository directory. If the path is a label, it will resolve to \
-          the path of the corresponding file. Note that remote repositories are executed \
-          during the analysis phase and thus cannot depends on a target result (the \
+          Returns a path from a string, label, or path. If this context is a \
+          <code>repository_ctx</code>, a relative path will resolve relative to the \
+          repository directory. If it is a <code>module_ctx</code>, a relative path will \
+          resolve relative to a temporary working directory for this module extension. \
+          If the path is a label, it will resolve to \
+          the path of the corresponding file. Note that remote repositories and module extensions \
+          are executed during the analysis phase and thus cannot depends on a target result (the \
           label should point to a non-generated file). If path is a path, it will return \
           that path as is.
           """,