doc: help_loc_structure -> help_project_structure (#3910)

* location is renamed to project in 8.4

Author: pesekon2

doc/help_loc_structure.odg

@@ -203,9 +203,9 @@ as follows:
 
 <!--
   original:
-  doc/help_loc_structure.odg
+  doc/help_project_structure.odg
 -->
-\image html "loc_struct.png" "Diagram of GRASS file structure"
+\image html "help_project_structure.png" "Diagram of GRASS file structure"
 
 \section Compiling_and_Installing_GRASS_Modules Compiling and Installing GRASS Modules
 

doc/help_project_structure.odg

@@ -25,7 +25,7 @@ FILES = \
 	$(ETC)/echo$(EXE) \
 	$(ETC)/license \
 	$(ETC)/VERSIONNUMBER \
-	$(HTMLDIR)/help_loc_struct.png \
+	$(HTMLDIR)/help_project_structure.png \
 	$(HTMLDIR)/grassdb.png \
 	$(HTMLDIR)/location.png \
 	$(HTMLDIR)/location-add.png \