Features:
    c7d84c5 PR #4980 Full `:ruby` support!
    c74ce33 PR #4624 timers: timer_start(), timer_stop()
    b8e6f04 PR #5205 `:CheckHealth` command

    47a15d0 PR #4865 file: Add buffered reading and writing
        *Much* faster shada file reading (important for startup time).

    71b3e20 PR #4723 jobstart() learned 'rpc'
        jobs and RPC channel IDs share the same "namespace".
        jobstart() can starts RPC channels, which allows scripts to handle
        'stderr' on a RPC channel, like a typical non-RPC job.
        jobpid()/jobstop() work on RPC "jobs".
        Deprecates rpcstart().

    4dc4efc PR #4449 man.vim rewrite
        `:Man` command is enabled by default.
        New features: completion, window handling, better parsing, and more.

    8a4e5b4 PR #4697 capture() function (renamed to execute())
        Supports nesting, including nested :redir.

    ae6db26 PR #5050 'rplugin manifest: default to XDG dir'
    a168228 PR #5214 Restore ":browse oldfiles".
    1f7304b Better handling of mouse-clicks on concealed chars.
    5ea4d58 PR #5026 terminal: Ensure b:term_title always has a value
    c002310 tui: Assume 256 colors in most cases.
    a2ecbc2 PR #4929 Always resize the :terminal
    a59330d PR #4925 api_info()
    a160590 PR #4813 allow setting cwd in jobstart(), termopen()
    74f6460 PR #4633: support "special" highlight (undercurl)
    5a5ef1c PR #3450 mouse: Implement horizontal scroll.

Windows support:
    All PRs now build on Appveyor targeting win32 and win64!
    Numerous fixes!

Fixes:
    e906111 PR #4646 Prevent data loss for process output streams
    7fa1baf PR #4798 'process.c: Fix block in teardown'
    c10fe01 Prevent endless loop in printdigraph(). (#5215)
    add41dc PR #5192 timers: Avoid crash after processing events
    006f9c0 PR #5195 Set the default value for 'packpath'
    6da7d68 PR #5025 Restore double click
    d622e9c readfile(): Less-disruptive readonly check.
        Fixes an issue where nvim unnecessarily "touched" open files.
    fe6ec75 PR #4964 Handle very long $XDG_DATA_DIRS.
    895f712 option: Do not expand options in XDG vars.
    1d8a076 server_init: Handle server_address_new() failure.
    be531ab PR #5042 Fix v:register for clipboard=unnamed,unnamedplus
    204f557 PR #4984 'Trigger TabNewEntered with <CTRL-W>T'
    1e93e24 PR #4851 synIDattr(): Return RRGGBB value for `fg#`.

Changes:
    acc5d08 PR #4690 'termguicolors' option enables "true color".
        NVIM_TUI_ENABLE_TRUE_COLOR is now ignored.