documentation: remove extraneous words

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Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/technical/parallel-checkout.txt

@@ -63,7 +63,7 @@ improvements over the sequential code, but there was still too much lock
 contention. A `perf` profiling indicated that around 20% of the runtime
 during a local Linux clone (on an SSD) was spent in locking functions.
 For this reason this approach was rejected in favor of using multiple
-child processes, which led to a better performance.
+child processes, which led to better performance.
 
 Multi-Process Solution
 ----------------------

Documentation/technical/partial-clone.txt

@@ -322,7 +322,7 @@ Footnotes
 
 [a] expensive-to-modify list of missing objects:  Earlier in the design of
     partial clone we discussed the need for a single list of missing objects.
-    This would essentially be a sorted linear list of OIDs that the were
+    This would essentially be a sorted linear list of OIDs that were
     omitted by the server during a clone or subsequent fetches.
 
 This file would need to be loaded into memory on every object lookup.

Documentation/technical/rerere.txt

@@ -145,7 +145,7 @@ Nested conflicts
 Nested conflicts are handled very similarly to "simple" conflicts.
 Similar to simple conflicts, the conflict is first normalized by
 stripping the labels from conflict markers, stripping the common ancestor
-version, and the sorting the conflict hunks, both for the outer and the
+version, and sorting the conflict hunks, both for the outer and the
 inner conflict.  This is done recursively, so any number of nested
 conflicts can be handled.