Улучшение структуры документации

docs/intro-eng.md

@@ -1,6 +1,8 @@
-# Naming
+# Basic Geomtric Computations
 
-## Prefixes
+## Naming 
+
+### Prefixes
 
 The library uses prefixes in names of types, constants and functions.
 
@@ -15,7 +17,7 @@ BGC_TWO_PI_FP64.
 The functions have prefix in the form **bgc_**. For example:
 bgc_versor_combine_fp32, bgc_matrix3x3_subtract_fp32.
 
-## Suffixes
+### Suffixes
 
 Suffixs of type ends the names of constats, types and functions of the library.
 The library uses two types of floating point numbers: **float** and  **double**
@@ -49,6 +51,8 @@ the type suffix: bgc_vector3_reset_fp64, bgc_radians_normalize_fp64.
 
 ## Entities
 
-- Vectors 2D and 3D
-- [Versors](./versor-eng.md)
+- [Vectors 2D](vector-eng.md)
+- Vectors 3D
+- [Quaternions](quaternion-eng.md)
+- [Versors](versor-eng.md)