Correct some grammar and spelling errors

Corrected few spelling errors and grammatical errors in the file.

Update requirements.md
Corrected some of the grammatical and spelling errors in the file.

Update index.md

Update requirements.md

Update markdown.md

Apply suggestion to doc/install/requirements.md

Apply suggestion to doc/user/markdown.md

Apply suggestion to doc/user/snippets.md

Apply suggestion to doc/user/snippets.md

doc/install/requirements.md

@@ -126,7 +126,7 @@ available when needed.
 
 Our [Memory Team](https://about.gitlab.com/handbook/engineering/development/enablement/memory/) is actively working to reduce the memory requirement.
 
-NOTE: **Note:** The 25 workers of Sidekiq will show up as separate processes in your process overview (such as `top` or `htop`) but they share the same RAM allocation since Sidekiq is a multithreaded application. Please see the section below about Unicorn workers for information about how many you need for those.
+NOTE: **Note:** The 25 workers of Sidekiq will show up as separate processes in your process overview (such as `top` or `htop`). However, they share the same RAM allocation, as Sidekiq is a multi-threaded application. See the section below about Unicorn workers for information about how many you need for those.
 
 ## Database
 

doc/user/markdown.md

@@ -76,7 +76,7 @@ NOTE: **Note:** We will flag any significant differences between Redcarpet and C
 If you have a large volume of Markdown files, it can be tedious to determine
 if they will display correctly or not. You can use the
 [diff_redcarpet_cmark](https://gitlab.com/digitalmoksha/diff_redcarpet_cmark)
-tool (not an officially supported product) to generate a list of files, and the
+tool (not an officially supported product) to generate a list of files and the
 differences between how RedCarpet and CommonMark render the files. It can give
 an indication if anything needs to be changed - often nothing will need
 to change.
@@ -253,7 +253,7 @@ Consult the [Emoji Cheat Sheet](https://www.webfx.com/tools/emoji-cheat-sheet/)
 > **Note:** The emoji example above uses hard-coded images for this documentation. The emoji,
 when rendered within GitLab, may appear different depending on the OS and browser used.
 
-Most emoji are natively supported on macOS, Windows, iOS, Android and will fallback to image-based emoji where there is lack of support.
+Most emoji are natively supported on macOS, Windows, iOS, Android, and will fall back on image-based emoji where there is no support.
 
 NOTE: **Note:** On Linux, you can download [Noto Color Emoji](https://www.google.com/get/noto/help/emoji/)
 to get full native emoji support. Ubuntu 18.04 (like many modern Linux distributions) has
@@ -272,7 +272,7 @@ in a box at the top of the document, before the rendered HTML content. To view a
 you can toggle between the source and rendered version of a [GitLab documentation file](https://gitlab.com/gitlab-org/gitlab/blob/master/doc/README.md).
 
 In GitLab, front matter is only used in Markdown files and wiki pages, not the other
-places where Markdown formatting is supported. It must be at the very top of the document,
+places where Markdown formatting is supported. It must be at the very top of the document
 and must be between delimiters, as explained below.
 
 The following delimiters are supported:
@@ -405,7 +405,7 @@ GFM recognizes special GitLab related references. For example, you can easily re
 an issue, a commit, a team member, or even the whole team within a project. GFM will turn
 that reference into a link so you can navigate between them easily.
 
-Additionally, GFM recognizes certain cross-project references, and also has a shorthand
+Additionally, GFM recognizes certain cross-project references and also has a shorthand
 version to reference other projects from the same namespace.
 
 GFM will recognize the following:

doc/user/snippets.md

@@ -147,8 +147,8 @@ snippet was created using the GitLab web interface the original line ending is W
 
 > Introduced in GitLab 10.8.
 
-Public snippets can not only be shared, but also embedded on any website. This
-allows us to reuse a GitLab snippet in multiple places and any change to the source
+Public snippets can not only be shared, but also embedded on any website. With
+this, you can reuse a GitLab snippet in multiple places and any change to the source
 is automatically reflected in the embedded snippet.
 
 To embed a snippet, first make sure that:
@@ -172,6 +172,6 @@ Here's how an embedded snippet looks like:
 
 <script src="https://gitlab.com/gitlab-org/gitlab-foss/snippets/1717978.js"></script>
 
-Embedded snippets are displayed with a header that shows the file name is defined,
+Embedded snippets are displayed with a header that shows the file name if it's defined,
 the snippet size, a link to GitLab, and the actual snippet content. Actions in
 the header allow users to see the snippet in raw format and download it.