fix(docs): Correct spelling and grammar in feature request template (#4490)

Minor corrections to spell and grammar in the feature request template.

## What type of PR is this? (check all applicable)

- [ ] Refactor
- [ ] Feature
- [ ] Bug Fix
- [ ] Optimization
- [x] Documentation Update
- [ ] Community Node Submission


## Have you discussed this change with the InvokeAI team?
- [ ] Yes
- [x] No, because:

This PR should be self explanatory.
      
## Have you updated all relevant documentation?
- [x] Yes
- [ ] No


## Description

Minor corrections to spell and grammar in the feature request template.

No code or behavioural changes.


## Related Tickets & Documents

<!--
For pull requests that relate or close an issue, please include them
below. 

For example having the text: "closes #1234" would connect the current
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request to issue 1234.  And when we merge the pull request, Github will
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- Related Issue #
- Closes #

## QA Instructions, Screenshots, Recordings

<!-- 
Please provide steps on how to test changes, any hardware or 
software specifications as well as any other pertinent information. 
-->

N/A

## Added/updated tests?

- [ ] Yes
- [x] No : _please replace this line with details on why tests
      have not been included_

There are no tests for the issue template.

## [optional] Are there any post deployment tasks we need to perform?

.github/ISSUE_TEMPLATE/FEATURE_REQUEST.yml

@@ -1,5 +1,5 @@
 name: Feature Request
-description: Commit a idea or Request a new feature
+description: Contribute a idea or request a new feature
 title: '[enhancement]: '
 labels: ['enhancement']
 # assignees:
@@ -9,14 +9,14 @@ body:
   - type: markdown
     attributes:
       value: |
-        Thanks for taking the time to fill out this Feature request!
+        Thanks for taking the time to fill out this feature request!
 
   - type: checkboxes
     attributes:
       label: Is there an existing issue for this?
       description: |
         Please make use of the [search function](https://github.com/invoke-ai/InvokeAI/labels/enhancement)
-        to see if a simmilar issue already exists for the feature you want to request
+        to see if a similar issue already exists for the feature you want to request
       options:
         - label: I have searched the existing issues
           required: true
@@ -36,7 +36,7 @@ body:
       label: What should this feature add?
       description: Please try to explain the functionality this feature should add
       placeholder: |
-        Instead of one huge textfield, it would be nice to have forms for bug-reports, feature-requests, ...
+        Instead of one huge text field, it would be nice to have forms for bug-reports, feature-requests, ...
         Great benefits with automatic labeling, assigning and other functionalitys not available in that form
         via old-fashioned markdown-templates. I would also love to see the use of a moderator bot 🤖 like
         https://github.com/marketplace/actions/issue-moderator-with-commands to auto close old issues and other things
@@ -51,6 +51,6 @@ body:
 
   - type: textarea
     attributes:
-      label: Aditional Content
+      label: Additional Content
       description: Add any other context or screenshots about the feature request here.
-      placeholder: This is a Mockup of the design how I imagine it <screenshot>
+      placeholder: This is a mockup of the design how I imagine it <screenshot>