Fixing documentation errors found within the Architecture Reference

section

The first error was found under the "row" tag description. Originally,
one of the optional attributes was "icry", this was changed to "incrx".
Since horizontal increments are in the x-axis.

The second error was found under the "region" tag description.
Originally, the description for the optional attribute "incry" was "An
expression specifying the horizontal increment between block
instantiations within the region.", horizontal was changed to vertical.

The third error was found under the "equivalent_sites" tag description.
Originally the note under the "direct" tag said "This tag is need only
if the pin_mapping of the site is defined as custom", need was changed
to needed.

Author: Srivat97

doc/src/arch/reference.rst

@@ -378,7 +378,7 @@ Grid Location Tags
 
         **Default:** ``0``
 
-    :opt_param incry:
+    :opt_param incrx:
         An expression specifying the horizontal increment between block instantiations within the region.
 
         **Default:** ``w``
@@ -442,7 +442,7 @@ Grid Location Tags
         An expression specifying the vertical repeat factor of the column.
 
     :opt_param incry:
-        An expression specifying the horizontal increment between block instantiations within the region.
+        An expression specifying the vertical increment between block instantiations within the region.
 
         **Default:** ``h``
 
@@ -965,7 +965,7 @@ The following tags are common to all ``<tile>`` tags:
                 Desctibes the mapping of a physical tile's port on the logical block's (pb_type) port.
                 ``direct`` is an option sub-tag of ``site``.
 
-                .. note:: This tag is need only if the pin_mapping of the ``site`` is defined as ``custom``
+                .. note:: This tag is needed only if the pin_mapping of the ``site`` is defined as ``custom``
 
                 Attributes:
                     - ``from`` is relative to the physical tile pins