Remove duplicated words in en/ru manuals

Thanks Kornel for suggesting regexp "\b(\w+)\s+\1\b".

lib/doc/Customization.lyx

@@ -19612,7 +19612,7 @@ name
 
 \end_inset
 
- may be be any valid identifier not used by a pre-existing Flex inset.
+ may be any valid identifier not used by a pre-existing Flex inset.
  The identifier may include spaces, but in that case the whole thing must
  be wrapped in quotes.
  Note that the definition of a flex inset 
@@ -19672,7 +19672,7 @@ name
 
 \end_inset
 
- may be be any valid identifier of branch defined in user's document.
+ may be any valid identifier of branch defined in user's document.
  The identifier may include spaces, but in that case the whole thing must
  be wrapped in quotes.
  The main purpose of this feature is to allow \SpecialChar LaTeX
@@ -20544,9 +20544,9 @@ status collapsed
 
 \end_inset
 
-] Force a a line break in the \SpecialChar LaTeX
+] Force a line break in the \SpecialChar LaTeX
- output before the inset starts and after
+ output before the inset starts and after the
- the inset ends.
+ inset ends.
  This assures the inset itself is output on its own lines, for parsing purposes.
 \end_layout
 

lib/doc/EmbeddedObjects.lyx

@@ -37956,7 +37956,7 @@ reference "tab:Units"
 \series bold
 !
 \series default
- in of of the two insets, the size is set so that the aspect ratio of the
+ in one of the two insets, the size is set so that the aspect ratio of the
  box content is kept.
  If no 
 \family sans

lib/doc/Math.lyx

@@ -4870,7 +4870,7 @@ bigr).
 \change_deleted -563046850 1563192735
  
 \change_unchanged
-Alternatively, parentheses can can 
+Alternatively, parentheses can 
 \change_deleted -563046850 1563192971
 either 
 \change_unchanged

lib/doc/UserGuide.lyx

@@ -13506,7 +13506,7 @@ automatic
 \change_unchanged
  
 \change_inserted -712698321 1524413747
-either the the standard \SpecialChar TeX
+either the standard \SpecialChar TeX
  font 
 \begin_inset Quotes eld
 \end_inset
@@ -48227,8 +48227,8 @@ reference "subsec:Numbering-depth"
 \change_inserted 5863208 1558620379
 You can typeset lines numbering in the output file by enabling the checkbox
  at the bottom.
- The functionality is handled by package lineno and and additional options
+ The functionality is handled by package lineno and additional options of
- of this package can be used as well.
+ this package can be used as well.
  The most common one are:
 \end_layout
 
@@ -50232,7 +50232,7 @@ do not
 \emph default
  track changes.
  In such documents, change-tracked text will be copied and pasted as is
- is (keeping 
+ (keeping 
 \emph on
 addition
 \emph default

lib/doc/ru/Additional.lyx

@@ -8190,7 +8190,7 @@ references
 deluxetable
 \family default
  (2.15).
- Если вам действительно действительно нужно использовать 
+ Если вам действительно нужно использовать 
 \family sans
 deluxetable
 \family default
@@ -11568,7 +11568,7 @@ Chk\SpecialChar TeX
 \end_layout
 
 \begin_layout Itemize
-Нет пробела перед скобками и/или после после них:
+Нет пробела перед скобками и/или после них:
 \begin_inset Newline newline
 \end_inset