Add rudimentary description to empty docs (#882)

Author: g-back

docs/_checks/41.md

@@ -4,7 +4,22 @@ cNumber: CHECK_41
 rfc: true
 ---
 
-todo
+Checks for empty lines and comment lines inside of statements.
+
+Examples:
+
+```abap
+READ TABLE lt_table
+
+INDEX 1 INTO ls_table.
+```
+
+```abap
+READ TABLE lt_table
+" read index 1
+INDEX 1 INTO ls_table.
+```
+
 
 ### Configuration
 ![Configuration](/img/41_conf.png)

docs/_checks/42.md

@@ -4,7 +4,18 @@ cNumber: CHECK_42
 rfc: true
 ---
 
-todo
+Checks for identical WHEN-Blocks.
+
+Example:
+
+```abap
+CASE lv_foo.
+  WHEN 1.
+    WRITE lv_bar.
+  WHEN 2.
+    WRITE lv_bar.  " <- identical to WHEN 1
+ENDCASE.
+```
 
 ### Configuration
 ![Configuration](/img/default_conf.png)

docs/_checks/78.md

@@ -5,4 +5,17 @@ rfc: true
 ---
 
 ### EC CI_SUBRC can be removed
-todo
+
+If the SUBRC is checked, the pseudo comment 'EC CI_SUBRC' can be removed.
+
+Example:
+
+```abap
+SELECT * FROM TADIR. "#EC CI_SUBRC  <- can be removed, since SUBRC is checked afterwards
+IF sy-subrc = 0.
+  ..
+ENDIF.
+```
+
+## Configuration
+![Configuration](/img/default_conf.png)

docs/_checks/79.md

@@ -5,6 +5,24 @@ rfc: true
 ---
 
 ### CLEAR as first use of variable
-todo
 
-Only works for local variables in global classes.
+Checks if a variable is cleared in it's first usage after it has been defined.
+
+Note: Only works for local variables in global classes.
+
+Example:
+
+```abap
+..
+METHOD foobar.
+
+  DATA lv_index TYPE i.
+  CLEAR lv_index. 
+  ..
+
+ENDMETHOD.
+..
+```
+
+## Configuration
+![Configuration](/img/default_conf.png)

docs/_checks/80.md

@@ -4,7 +4,12 @@ cNumber: CHECK_80
 rfc: true
 ---
 
-### Space before colon
-todo
+### Spaces before colon
 
-[https://github.com/SAP/styleguides/blob/master/clean-abap/CleanABAP.md#condense-your-code](https://github.com/SAP/styleguides/blob/master/clean-abap/CleanABAP.md#condense-your-code)
+Checks for spaces before colons.
+
+See also
+[https://github.com/SAP/styleguides/blob/master/clean-abap/CleanABAP.md#condense-your-code](https://github.com/SAP/styleguides/blob/master/clean-abap/CleanABAP.md#condense-your-code) for reference.
+
+## Configuration
+![Configuration](/img/default_conf.png)