[docs] Improve docs: fix consistency of dots in C API and add notes a…

…bout new ``time-costs`` Python-package build option (#5554)

include/LightGBM/c_api.h

@@ -597,10 +597,10 @@ LIGHTGBM_C_EXPORT int LGBM_BoosterLoadModelFromString(const char* model_str,
 
 /*!
  * \brief Get parameters as JSON string.
- * \param handle Handle of booster.
- * \param buffer_len Allocated space for string.
- * \param[out] out_len Actual size of string.
- * \param[out] out_str JSON string containing parameters.
+ * \param handle Handle of booster
+ * \param buffer_len Allocated space for string
+ * \param[out] out_len Actual size of string
+ * \param[out] out_str JSON string containing parameters
  * \return 0 when succeed, -1 when failure happens
  */
 LIGHTGBM_C_EXPORT int LGBM_BoosterGetLoadedParam(BoosterHandle handle,

python-package/README.rst

@@ -163,7 +163,7 @@ By default, installation in environment with 32-bit Python is prohibited. Howeve
 
 It is **strongly not recommended** to use this version of LightGBM!
 
-Build with time costs output
+Build with Time Costs Output
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 .. code:: sh
@@ -217,6 +217,8 @@ Run ``python setup.py install --hdfs`` to enable HDFS support. All requirements
 
 Run ``python setup.py install --bit32``, if you want to use 32-bit version. All requirements from `Build 32-bit Version with 32-bit Python section <#build-32-bit-version-with-32-bit-python>`__ apply for this installation option as well.
 
+Run ``python setup.py install --time-costs``, if you want to output time costs for different internal routines. All requirements from `Build with Time Costs Output section <#build-with-time-costs-output>`__ apply for this installation option as well.
+
 If you get any errors during installation or due to any other reasons, you may want to build dynamic library from sources by any method you prefer (see `Installation Guide <https://github.com/microsoft/LightGBM/blob/master/docs/Installation-Guide.rst>`__) and then just run ``python setup.py install --precompile``.
 
 Build Wheel File