Help: Link to COMPILE_LANGUAGE genex from target_compile_options

Issue: #24639

Help/command/target_compile_options.rst

@@ -50,6 +50,10 @@ See Also
 
 * For file-specific settings, there is the source file property :prop_sf:`COMPILE_OPTIONS`.
 
+* This command adds compile options for all languages in a target.
+  Use the :genex:`COMPILE_LANGUAGE` generator expression to specify
+  per-language compile options.
+
 * :command:`target_compile_features`
 * :command:`target_link_libraries`
 * :command:`target_link_directories`

Help/prop_tgt/COMPILE_OPTIONS.rst

@@ -11,6 +11,10 @@ The options will be added after after flags in the
 variables, but before those propagated from dependencies by the
 :prop_tgt:`INTERFACE_COMPILE_OPTIONS` property.
 
+This property adds compile options for all languages in a target.
+Use the :genex:`COMPILE_LANGUAGE` generator expression to specify
+per-language compile options.
+
 This property is initialized by the :prop_dir:`COMPILE_OPTIONS` directory
 property when a target is created, and is used by the generators to set
 the options for the compiler.