fix(docs): typos in installation.md regarding Qt backend (#580)

* Fix typos in installation.md regarding Qt backend

* added changes to CHANGELOG.md

Took note of the changes in PR #580 regarding spelling mistakes in the installation.md

Author: strniko

CHANGELOG.md

@@ -24,6 +24,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   [#560](https://github.com/jeertmans/manim-slides/pull/560)
 - Update the template in the *Customize your RevealJS slides* section.
   [#565](https://github.com/jeertmans/manim-slides/pull/565)
+- Fix spelling mistakes in the `installation.md` regarding Qt backend.
+  [@strniko](https://github.com/strniko) [#580](https://github.com/jeertmans/manim-slides/pull/580)
 
 (unreleased-fixed)=
 ### Fixed

docs/source/installation.md

@@ -153,12 +153,12 @@ Nix does not currently support `manimgl`.
 ## When you need a Qt backend
 
 Before `v5.1`, Manim Slides automatically included PySide6 as
-a Qt backend. As only `manim-slides present` and `manim-slides wizard`
-command need a graphical library, and installing PySide6 on all platforms
-and Python version can be sometimes complicated, Manim Slides chooses
-**not to include** any Qt backend.
+a Qt backend. As only the `manim-slides present` and `manim-slides wizard`
+commands need a graphical library, and installing PySide6 on all platforms
+and Python versions can sometimes be complicated, Manim Slides chooses
+**not to include** any Qt backends.
 
-The use can choose between PySide6 (best) and PyQt6, depending on their
+The user can choose between PySide6 (best) and PyQt6, depending on their
 availability and licensing rules.
 
 As of `v5.1`, you **need** to have Qt bindings installed to use