Function is_c_language 

pub fn is_c_language(lang: &Language) -> bool

Check whether a tree_sitter::Language is the C grammar.

Used by crate::repo_map to gate C-specific call-edge extraction — the struct-literal initializer fnptr post-pass (I#55, 4.1.5). C codebases dispatch via tables of function pointers (Linux file_operations, redis redisCommandTable, libuv handle vtables) — the post-pass emits one synthetic edge per identifier found inside an initializer_list, either designated (.read = my_read) or positional ({"get", getCommand}). Same node-kind-count proxy as is_rust_language.