Add svg package and a few helpers (#67)

Introducing SVG, to inline vector graphics in your HTML! 🥳

Fix code in readme (#69)

Broken in #66.

Update license year (#68)

Streamline HTML element API (#66)

There were a lot of elements previously, like `Em`, `H1`, and a lot more, that took a string as the first argument previously. This was weird when you wanted to mix elements to output html like `<strong><em>…</em></strong>` or `<h1>Something <em>something</em> something</h1>`. gomponents is not an HTML validator, so I want people to be able to use elements however they please, also without text content.

This also means that all elements now have the same API.

Use g.If in HTML5 helper (#65)

Inlining looks much nicer.

Return Node from all helpers instead of NodeFunc (#62)

This makes it clearer that the helpers return a `Node` of any kind, and that the type is not important.

This also streamlines the API, as attribute helpers already return just `Node`.

Add data- attribute helper (#61)

Fixes #49.

Add test for InputHidden (#60)

Add aria-* and role attributes (#59)

Fixes #50.

Add If helper function (#57)

Used to inline conditional nodes.

Change main example to be the dot-import version (#56)

Simplify available elements (#55)

`a`, `form`, `img`, `input`, `label`, `option`, `progress`, `select`, and `textarea` are now just regular elements (without helper parameters), because:
- Sometimes the use case doesn't fit (`a` as anchor without href, for example)
- There's no reason these are special among the others, so streamlining them makes sense

Also added new attributes `action`, `alt`, `for`, `method` that I had somehow missed.

Rename Document to Doctype (#54)

Move elements and attributes into html package (#52)

This makes it easier to use dot-imports.

Also updated the readme and examples with new usage, and move the `Classes` helper into the `components` package.

Minor refactoring and comment changes (#51)

Add example with dot imports (#47)

Add svg element (#46)

Also add `cols` and `rows` attributes.

Fixes #43.

Add NodeType which replaces the Placer interface (#45)

The `Placer` interface was a weird interface that tried to abstract away nodes being elements or attributes, but it doesn't really make sense. Now `Nodes` just have a `NodeType`.

Render correct HTML5 (#44)

Previously, elements of kind void and empty elements generally would be rendered auto-closing (with a final `/` character in the start tag), which is allowed sometimes but arguably wrong. See https://dev.w3.org/html5/spec-LC/syntax.html#end-tags

This created problems with for example `textarea` and `script`, which cannot be auto-closing, or the browser renders it wrong.

Also clarified in the docs that this library outputs HTML5.

Fixes #42.

Add package docs (#41)

Also update readme with features.

Add Map function (#40)

`Map` makes it easier to build lists of elements without having to iterate.

Render to Writer instead of string (#39)

The Render function has been changed to take a `Writer` instead of returning a string. This makes it possible to generate documents without having the whole content in memory.

This also removes the `gomponents.Write` function, which is now redundant.

Furthermore, the `el.Document` function has been changed to only take one child, as multiple children never make sense for it. (It's not even a child, more a sibling.)

Remove fmt.Sprintf call in attribute Render (#38)

Just concatenating the strings is much faster.

Before:

```
make benchmark
go test -bench=.
goos: darwin
goarch: amd64
pkg: github.com/maragudk/gomponents
BenchmarkAttr/boolean_attributes-8         	 8194791	       139 ns/op
BenchmarkAttr/name-value_attributes-8      	 5143292	       229 ns/op
PASS
ok  	github.com/maragudk/gomponents	2.841s
```

After:

```
make benchmark
go test -bench=.
goos: darwin
goarch: amd64
pkg: github.com/maragudk/gomponents
BenchmarkAttr/boolean_attributes-8         	16755404	        67.0 ns/op
BenchmarkAttr/name-value_attributes-8      	10208625	       116 ns/op
PASS
ok  	github.com/maragudk/gomponents	2.702s
```

Pass attributes as pointers (#37)

Add HTML5 document template (#36)

Add attribute helpers (#35)

Also refactor tests to be table-driven, for readability.

Add element helpers and refactor (#34)

This change adds a lot of element helpers, and refactors:
- helpers into simple, text, and other helpers
- most tests into table-driven tests, so they're easier to read

Thanks to @oderwat for pushing me to improve the tests. 😉

Add contributing instructions (#33)

Add br and hr element helpers (#30)

Remove "fmt" import in readme example (#31)

Also style menu in simple example slightly.

Don't render or error on nil children (#32)

This makes it easier to e.g. conditionally skip a component for rendering.

Add Group function to group Nodes (#29)

Update package doc for gomponents (#28)

Use HTMLEscapeString in Textf (#27)

Add remaining sectioning elements as helpers (#25)

Fixes #22.

Use HTMLEscapeString (#24)

HTMLEscaper is not needed with strings.

Update readme with blog post link (#23)

Group element helpers in different files (#21)

According to the section at https://developer.mozilla.org/en-US/docs/Web/HTML/Element

Add space before auto-closing element (#20)

Add convenience helpers for form elements (#19)

Introduce Placer interface (#18)

When implemented, the `Place` method of the `Placer` interface tells `Render` in `El` where to put a Node. This is relevant for helpers that want to be rendered like attributes, inside the parent element.

Fixes the bug where `attr.Classes` was rendered outside the element.

Add Textf function (#17)

Like Text, but calls fmt.Sprintf before rendering.

Add better example in readme (#16)

Add children varargs to h1-6, b, strong, i, em, img helpers (#15)

This makes it possible to add attributes.

Make attr.Classes a map type (#14)

This makes the usage syntax prettier. Instead of `attr.Classes(map[string]bool{})`, we can just use `attr.Classes{}`.

Add simple example (#13)

Add a test for attr.String (#12)

Add a Write function (#11)

Add a lot of common elements (#10)

Especially add elements that are either used in every document, that nearly always have text content, or that are almost always used with certain attributes.

Don't render twice with children (#9)

Add package el with element helpers (#8)

Add package attr with attribute helpers (#7)

Make NodeFunc and attr implement fmt.Stringer (#6)

Try out codecov.io (#5)

Add Makefile (#4)

Create codeql-analysis.yml (#3)

Add godoc link to readme (#2)

Add package documentation (#1)

Add first implementation of Node, El, Attr, Text