Tree-sitter doc fixes (bug#60524)

Tree-sitter doc fixes (bug#60524)

* doc/lispref/modes.texi (Parser-based Font Lock):
Replace :lang with :language.

* doc/lispref/parsing.texi (Language Grammar): Replace
treesit-load-suffixes with dynamic-library-suffixes.
(Retrieving Nodes): Fix function names.
(Tree-sitter Major Modes): Fix treesit-ready-p args.
Fix pxref to Parser-based Indentation.
(Tree-sitter C API): Fix function names.

* lisp/treesit.el (treesit--simple-indent-eval): Remove cond BODY
duplicated from CONDITION.
(treesit)<define-short-documentation-group>: Fix function names.