Maciejedits: Website feature upgrade and some minor text edits on the mkdocs.yml

Website feature upgrade and some minor text edits on the mkdocs.yml

1. Change the website title to the full name of the course (rephrasing)
2. Change website description (rephrasing)
3. Setting up site search feature (plugin)
4. Setting up navigation feature (theme:feature)
5. Update copyright date (cosmetics)

mkdocs.yml

-site_name: mathforquantum
+site_name: Mathematics for Quantum Physics
 repo_url: https://gitlab.kwant-project.org/mathematics-for-quantum-physics/lectures
 repo_name: source
 edit_uri: edit/master/src/
 site_description: |
-  Lecture notes for TN3105 - Mathematics for Quantum Physics
+  Lecture notes for the TU Delft course TN3105 - Mathematics for Quantum Physics
 nav:
   - Intro: 'index.md'
   - Complex Numbers: '1_complex_numbers.md'
@@ -21,7 +21,12 @@ theme:
   palette:
     primary: 'white'
     accent: 'indigo'
+  features:
+    - navigation.instant
 
+plugins:
+  - search
+  
 markdown_extensions:
   - mdx_math:
       enable_dollar_delimiter: True
@@ -44,4 +49,5 @@ extra_javascript:
   - 'scripts/thebelab-custom.js'
   - 'scripts/mathjaxhelper.js'
   - 'scripts/thebelabhelper.js'
-copyright: "Copyright © 2019 Delft University of Technology, CC-BY-SA 4.0."
+
+copyright: "Copyright © 2019-2022 Delft University of Technology, CC-BY-SA 4.0."