Support syntax highlighting for Meson options file (#3534)

See also: https://mesonbuild.com/Build-options.html#build-options

data/filedefs/filetypes.Meson.conf

@@ -2,7 +2,7 @@
 
 [keywords]
 primary=and break continue elif else endforeach endif false foreach if in not or true
-identifiers=add_global_arguments add_global_link_arguments add_languages add_project_arguments add_project_link_arguments add_test_setup alias_target assert benchmark both_libraries build_target configuration_data configure_file custom_target declare_dependency dependency disabler environment error executable files find_library find_program generator get_option get_variable import include_directories install_data install_headers install_man install_subdir is_disabler is_variable jar join_paths library message project run_command run_target set_variable shared_library shared_module static_library subdir subdir_done subproject summary test vcs_tag warning
+identifiers=add_global_arguments add_global_link_arguments add_languages add_project_arguments add_project_link_arguments add_test_setup alias_target assert benchmark both_libraries build_target configuration_data configure_file custom_target declare_dependency dependency disabler environment error executable files find_library find_program generator get_option get_variable import include_directories install_data install_headers install_man install_subdir is_disabler is_variable jar join_paths library message option project run_command run_target set_variable shared_library shared_module static_library subdir subdir_done subproject summary test vcs_tag warning
 
 [lexer_properties=Python]
 

data/filetype_extensions.conf

@@ -52,7 +52,7 @@ Lua=*.lua;
 Make=*.mak;*.mk;GNUmakefile;makefile;Makefile;makefile.*;Makefile.*;
 Markdown=*.mdml;*.markdown;*.md;*.mkd;*.mkdn;*.mdwn;*.mdown;*.mdtxt;*.mdtext;
 Matlab/Octave=*.m;
-Meson=meson.build;
+Meson=meson.build;meson.options;meson_options.txt;
 Nim=*.nim;
 NSIS=*.nsi;*.nsh;
 Objective-C=*.m;*.mm;*.h;