chore: unify formatting in ISSUE_TEMPLATE's (open-telemetry#426)

* chore: unify formatting in ISSUE_TEMPLATE's

* chore: add ?

* chore: replace "plugin" with "instrumentation"

Co-authored-by: Valentin Marchaud <contact@vmarchaud.fr>

.github/ISSUE_TEMPLATE/bug_report.md

@@ -4,7 +4,9 @@ about: Create a report to help us improve
 labels: bug
 ---
 
+<!-- 
 Please answer these questions before submitting a bug report.
+-->
 
 ### What version of OpenTelemetry are you using?
 
@@ -13,7 +15,9 @@ Please answer these questions before submitting a bug report.
 
 
 ### What did you do?
+<!-- 
 If possible, provide a recipe for reproducing the error.
+-->
 
 
 ### What did you expect to see?
@@ -23,4 +27,7 @@ If possible, provide a recipe for reproducing the error.
 
 
 ### Additional context
+<!-- 
 Add any other context about the problem here.
+-->
+

.github/ISSUE_TEMPLATE/discussion.md

@@ -10,3 +10,4 @@ labels: discussion
 
 - [ ] This only affects the JavaScript OpenTelemetry library
 - [ ] This may affect other libraries, but I would like to get opinions here first
+

.github/ISSUE_TEMPLATE/feature_request.md

@@ -4,17 +4,30 @@ about: Suggest an idea for this project
 labels: feature-request
 ---
 
+<!--
 **NB:** Before opening a feature request against this repo, consider whether the feature should/could be implemented in the [other OpenTelemetry client libraries](https://github.com/open-telemetry/). If so, please [open an issue on opentelemetry-specification](https://github.com/open-telemetry/opentelemetry-specification/issues/new) first.
+-->
 
-
-**Is your feature request related to a problem? Please describe.**
+### Is your feature request related to a problem? Please describe
+<!--
 A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
+-->
+
 
-**Describe the solution you'd like**
+### Describe the solution you'd like to see
+<!-- 
 A clear and concise description of what you want to happen.
+-->
+
 
-**Describe alternatives you've considered**
+### Describe alternatives you've considered
+<!-- 
 A clear and concise description of any alternative solutions or features you've considered.
+-->
 
-**Additional context**
+
+### Additional context
+<!-- 
 Add any other context or screenshots about the feature request here.
+-->
+

.github/ISSUE_TEMPLATE/plugin_request.md

@@ -1,30 +1,32 @@
 ---
-name: Plugin request
-about: Create a report to add support for plugin
-labels: plugin-request
+name: Instrumentation request
+about: Create a report to add support for an instrumentation
+labels: instrumentation-request
 ---
 
 <!--
-**NB:** Before opening a plugin support request against this repo, consider whether the plugin should/could be implemented in the [other OpenTelemetry client libraries](https://github.com/open-telemetry/). If so, please [open an issue on opentelemetry-specification](https://github.com/open-telemetry/opentelemetry-specification/issues/new) first.
+**NB:** Before opening an instrumentation request against this repo, consider whether the instrumentation should/could be implemented in the [other OpenTelemetry client libraries](https://github.com/open-telemetry/). If so, please [open an issue on opentelemetry-specification](https://github.com/open-telemetry/opentelemetry-specification/issues/new) first.
 
-You are welcome to try out the [plugin api](https://github.com/open-telemetry/opentelemetry-js/blob/main/doc/plugin-guide.md) to build your own plugin. If you do try out the plugin api, please let us know if you have any questions/feedback.
+You are welcome to try to build your own instrumentation. If you do, please let us know if you have any questions/feedback.
 -->
 
-**Is your plugin request related to a problem? Please describe.**
+### Is your instrumentation request related to a problem? Please describe
 <!--
 A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
 -->
 
-**Is it applicable for Node or Browser or both**
 
-**Do you expect this plugin to be commonly used**
+### Is it applicable for Node or Browser or both?
+
+
+### Do you expect this instrumentation to be commonly used?
 Weekly Downloads:
 
-**What version of plugin are you interested in using**
+### What version of instrumentation are you interested in using?
 Versions:
 
-**Additional context**
+### Additional context
 <!--
-Add any other context or screenshots about the plugin request here.
+Add any other context or screenshots about the instrumentation request here. Is there a reference you could point for the well-defined lifecycle methods?
 -->
-- **Is there a reference you could point for the well-defined lifecycle methods**
+