more about environment
add API to get most inner definition at specific location
rename specific location information API
rename C API and remove useless Vim API
add API to get expression extent and statement extent
add API to get extent of classes and functions
forget adding methods as functions
add API to get parameter extent
remove useless lambda expressions
rename implementation functions and add foldings
add API to get extent of namespace
Merge branch 'add/more_extent_APIs'