fix(github): improve formatting of issue template spoilers (#311)

- I originally made the spoilers and while they work (and I would say
  improve readability a good bit), there's also some issues with them
  - I've used them a ton more now so know how to workaround most
    of the issues with them now

- fix: use HTML `code` tag inside of `summary` tag, can't use backticks
  - was mixing MD and HTML before, and this doesn't always work and
    didn't work on GitHub, they just had backticks

- fix: don't duplicate the file name in the heading, just make the
  `summary` have a heading inside it instead
  - use an `h4` same as the `####` that it was before

- feat: add syntax highlighting by adding code blocks for each code
  snippet
  - js for rollup.config.js, json5 for tsconfig (it has comments,
    trailing commas, etc (actually a custom parser, but json5 is close
    enough)), json for package.json, and text for verbose logs
  - also, a lot of people sometimes just paste the code with no code
    block and it formats terribly, so this should help defer that
    (as well as any potential issues that can crop up with unindented
    blocks)
    - the `envinfo` text code block seems to be working well, so
      hopefully this will improve issues too

.github/issue_template.md

@@ -18,42 +18,50 @@
 
 ```
 
-#### rollup.config.js
-
 <!--- paste your rollup config below if relevant --->
 <details>
-  <summary>`rollup.config.js`: </summary>
+  <summary><h4><code>rollup.config.js</code></h4>: </summary>
 
-<!--- INSERT rollup.config.js HERE --->
+<!--- INSERT rollup.config.ts IN THE CODE SNIPPET BELOW --->
 
-</details>
+```js
 
-#### tsconfig.json
+```
+
+</details>
 
 <!--- paste your tsconfig.json below if relevant --->
 <details>
-  <summary>`tsconfig.json`: </summary>
+  <summary><h4><code>tsconfig.json</code></h4>: </summary>
 
-<!--- INSERT tsconfig.json HERE --->
+<!--- INSERT tsconfig.json IN THE CODE SNIPPET BELOW --->
 
-</details>
+```json5
+
+```
 
-#### package.json
+</details>
 
 <!--- paste your package.json below if relevant --->
 <details>
-  <summary>`package.json`: </summary>
+  <summary><h4><code>package.json</code></h4>: </summary>
 
-<!--- INSERT package.json HERE --->
+<!--- INSERT package.json IN THE CODE SNIPPET BELOW --->
 
-</details>
+```json
+
+```
 
-#### plugin output with verbosity 3
+</details>
 
 <!--- add verbosity verbosity: 3 to plugin options and attach output if relevant (censor out anything sensitive) --->
 <details>
-  <summary>plugin output with verbosity 3: </summary>
+  <summary><h4>plugin output with verbosity 3</h4>: </summary>
 
-<!--- INSERT plugin output HERE or attach --->
+<!--- INSERT plugin output IN THE CODE SNIPPET BELOW or attach --->
+
+```text
+
+```
 
 </details>