fix: ignore punctuation at end of URL #157

Problem:
URLs in help docs may be followed by "." or ",", but it's usually not
intended as part of the URL.

Examples from neovim/neovim#36597:

    https://luarocks.org,
    https://neovim.io/doc/,

Solution:
- Treat "." as a word.
- Assume that `)].,` at the end of a URL is not part of the URL.

Now NESTED parens work:

    (https://neovim.io/doc/user/vimfn.html#get()-blob)

but it's not possible to support a trailing closing paren ")":

    (https://neovim.io/doc/user/api.html#nvim_input())

workaround: URL-encode the trailing paren:

    (https://neovim.io/doc/user/api.html#nvim_input%28%29)

URL cannot contain a closing bracket `]` anywhere in the URL.
(Workaround: URL-encode the bracket.) This is a tradeoff so that
markdown hyperlinks work:

    [https://example.com](https://example.com)

Bonus(?): now the inline code in this example is recognized:

    `foo`.bar

Author: justinmk

.editorconfig

@@ -4,7 +4,10 @@ root = true
 charset = utf-8
 end_of_line = lf
 insert_final_newline = true
-trim_trailing_whitespace = true
+
+[*.txt]
+# Some test files have intentional whitespace at EOL.
+trim_trailing_whitespace = false
 
 [*.{json,toml,yml,gyp}]
 indent_style = space

README.md

@@ -32,6 +32,7 @@ Overview
     nature; parsing the contents would require loading a "child" language
     (injection). See [#2](https://github.com/neovim/tree-sitter-vimdoc/issues/2).
   - the terminating `<` (and any following whitespace) is discarded (anonymous).
+- `url` intentionally does not capture `.,)` at the end of the URL. See also [Known issues](#known-issues).
 - `h1` = "Heading 1": `======` followed by text and optional `*tags*`.
 - `h2` = "Heading 2": `------` followed by text and optional `*tags*`.
 - `h3` = "Heading 3": UPPERCASE WORDS, followed by optional `*tags*`, followed
@@ -45,8 +46,11 @@ Known issues
 - Spec requires that `codeblock` delimiter ">" must be preceded by a space
   (" >"), not a tab. But currently the grammar doesn't enforce this. Example:
   `:help lcs-tab`.
-- `url` doesn't handle _surrounding_ parens. E.g. `(https://example.com/#yay)` yields `word`
-- `url` doesn't handle _nested_ parens. E.g. `(https://example.com/(foo)#yay)`
+- `url` cannot contain a closing bracket `]` anywhere in the URL. (Workaround:
+  URL-encode the bracket.) This is a tradeoff so that markdown hyperlinks work:
+  ```
+  [https://example.com](https://example.com)
+  ```
 - `column_heading` currently only recognizes tilde `~` preceded by space (i.e.
   `foo ~` not `foo~`). This covers 99% of :help files.
 - `column_heading` children should be plaintext, but currently are parsed as `$._atom`.
@@ -55,8 +59,8 @@ Known issues
 TODO
 ----
 
-- `tag_heading` : line(s) containing only tags, typically implies a "heading"
-  before a block.
+- `h4` ("tag heading") : a line containing only tags, or ending with a tag, is
+  a "h4" heading.
 
 Release
 -------

grammar.js

@@ -41,7 +41,7 @@ module.exports = grammar({
       $._atom_common,
     ),
     word: ($) => choice(
-      token(prec(-1, /[^,(\[\n\t ]+/)),
+      token(prec(-1, /[^.,(\[\n\t ]+/)),
       $._word_common,
     ),
 
@@ -89,11 +89,14 @@ module.exports = grammar({
       /\{\{+[0-9]*/,
 
       '(',
+      ')',
       '[',
+      ']',
       '~',
       // NOT codeblock: random ">" in middle of the motherflippin text.
       '>',
       ',',
+      '.',
     ),
 
     note: () => choice(
@@ -223,7 +226,7 @@ module.exports = grammar({
       '*', '*'),
 
     // URL without surrounding (), [], etc.
-    url_word: () => /https?:[^\n\t)\] ]+/,
+    url_word: () => /https?:\/\/[^\n\t\] ]*[^\n\t )\].,]/,
     url: ($) => choice(
       // seq('(', field('text', prec.left(alias($.url_word, $.word))), token.immediate(')')),
       // seq('[', field('text', prec.left(alias($.url_word, $.word))), token.immediate(']')),