docs: indentiation fixed in a contributing guide

Author: mpusz

CONTRIBUTING.md

@@ -8,11 +8,11 @@
 If you are looking for a good issue to start with, please check the following:
 
 - [good first issue](https://github.com/mpusz/mp-units/labels/good%20first%20issue) - issues that
- should be pretty simple to implement,
+  should be pretty simple to implement,
 - [help wanted](https://github.com/mpusz/mp-units/labels/help%20wanted) - issues that typically are
- a bit more involved than beginner issues,
+  a bit more involved than beginner issues,
 - [high priority](https://github.com/mpusz/mp-units/labels/high%20priority) - things to fix ASAP
- but often of higher complexity.
+  but often of higher complexity.
 
 
 ## Gitpod
@@ -46,28 +46,28 @@ if you want to set up a development environment on your local machine.
 
 [`user.mp-units.build:all`](#user.mp-units.build-all){ #user.mp-units.build-all }
 
- Enables compilation of all the source code, including tests and examples. To support this, it requires some additional Conan build dependencies described in
- [Repository directory tree and dependencies](https://mpusz.github.io/mp-units/latest/getting_started/project_structure#cmake-projects-and-dependencies).
- It also runs unit tests during the Conan build (unless
- [`tools.build:skip_test`](https://docs.conan.io/2/reference/commands/config.html?highlight=tools.build:skip_test#conan-config-list)
- configuration property is set to `True`).
+:   Enables compilation of all the source code, including tests and examples. To support this, it requires some additional Conan build dependencies described in
+    [Repository directory tree and dependencies](https://mpusz.github.io/mp-units/latest/getting_started/project_structure#cmake-projects-and-dependencies).
+    It also runs unit tests during the Conan build (unless
+    [`tools.build:skip_test`](https://docs.conan.io/2/reference/commands/config.html?highlight=tools.build:skip_test#conan-config-list)
+    configuration property is set to `True`).
 
- [conan build all support]: https://github.com/mpusz/mp-units/releases/tag/v2.2.0
+    [conan build all support]: https://github.com/mpusz/mp-units/releases/tag/v2.2.0
 
 [`user.mp-units.build:skip_la`](#user-skip-la){ #user-skip-la }
 
- If `user.mp-units.build:all` is enabled, among others, Conan installs the external
- [wg21-linear_algebra](https://conan.io/center/recipes/wg21-linear_algebra)
- dependency and enables the compilation of linear algebra-based tests and usage examples.
- Such behavior can be disabled with this option.
+:   If `user.mp-units.build:all` is enabled, among others, Conan installs the external
+    [wg21-linear_algebra](https://conan.io/center/recipes/wg21-linear_algebra)
+    dependency and enables the compilation of linear algebra-based tests and usage examples.
+    Such behavior can be disabled with this option.
 
- [conan skip la support]: https://github.com/mpusz/mp-units/releases/tag/v2.2.0
+    [conan skip la support]: https://github.com/mpusz/mp-units/releases/tag/v2.2.0
 
 [`user.mp-units.analyze:clang-tidy`](#user.mp-units.analyze-clang-tidy){ #user.mp-units.analyze-clang-tidy }
 
- Enables clang-tidy analysis.
+:   Enables clang-tidy analysis.
 
- [conan clang-tidy support]: https://github.com/mpusz/mp-units/releases/tag/v2.2.0
+    [conan clang-tidy support]: https://github.com/mpusz/mp-units/releases/tag/v2.2.0
 
 
 ### CMake options for mp-units project developers
@@ -76,25 +76,25 @@ if you want to set up a development environment on your local machine.
 
 :   [:octicons-tag-24: 2.2.0][cmake build la support] · :octicons-milestone-24: `ON`/`OFF` (Default: `ON`)
 
- Enables building code depending on the linear algebra library.
+    Enables building code depending on the linear algebra library.
 
- [cmake build la support]: https://github.com/mpusz/mp-units/releases/tag/v2.2.0
+    [cmake build la support]: https://github.com/mpusz/mp-units/releases/tag/v2.2.0
 
 [`MP_UNITS_DEV_IWYU`](#MP_UNITS_DEV_IWYU){ #MP_UNITS_DEV_IWYU }
 
 :   [:octicons-tag-24: 2.2.0][cmake iwyu support] · :octicons-milestone-24: `ON`/`OFF` (Default: `OFF`)
 
- Enables include-what-you-use analysis.
+    Enables include-what-you-use analysis.
 
- [cmake iwyu support]: https://github.com/mpusz/mp-units/releases/tag/v2.2.0
+    [cmake iwyu support]: https://github.com/mpusz/mp-units/releases/tag/v2.2.0
 
 [`MP_UNITS_DEV_CLANG_TIDY`](#MP_UNITS_DEV_CLANG_TIDY){ #MP_UNITS_DEV_CLANG_TIDY }
 
 :   [:octicons-tag-24: 2.2.0][cmake clang-tidy support] · :octicons-milestone-24: `ON`/`OFF` (Default: `OFF`)
 
- Enables clang-tidy analysis.
+    Enables clang-tidy analysis.
 
- [cmake clang-tidy support]: https://github.com/mpusz/mp-units/releases/tag/v2.2.0
+    [cmake clang-tidy support]: https://github.com/mpusz/mp-units/releases/tag/v2.2.0
 
 
 ### Building the entire repository
@@ -167,15 +167,15 @@ After that, you can either:
 
 - easily [start a live server to preview the documentation as you write](https://squidfunk.github.io/mkdocs-material/creating-your-site/#previewing-as-you-write)
 
-```shell
-mkdocs serve
-```
+    ```shell
+    mkdocs serve
+    ```
 
 - [build the documentation](https://squidfunk.github.io/mkdocs-material/creating-your-site/#building-your-site)
 
-```shell
-mkdocs build
-```
+    ```shell
+    mkdocs build
+    ```
 
 ### Generating API reference