chore(testables): default to `termopen` test executor if not using `n…

…eotest` (mrcjkb#434)

docs(changelog): prepare release

docs(changelog): prepare release

fix(lsp): force-extend capabilities with detected plugin capabilities

fix(lsp): inability to load rust-analyzer.json without rust-analzyer key

fix(lsp): error when opening a rust file that does not exist (mrcjkb#405

)

docs(changelog): update

fix(lsp): register `snippetSupport` capability only if using nvim >= …

…0.10

fix(ui): don't override Neovim defaults in default `float_win_config`

docs(vimdoc): add `FloatWinConfig` docs