Remove C# Diagnostic Support documentation note

This hasn't been true since ycmd pull request #44.

README.md

@@ -25,7 +25,6 @@ YouCompleteMe: a code-completion engine for Vim
     - [Semantic completion for other languages](#semantic-completion-for-other-languages)
     - [Writing new semantic completers](#writing-new-semantic-completers)
     - [Diagnostic display](#diagnostic-display)
-    - [C# diagnostic support](#c-diagnostic-support)
     - [Diagnostic highlighting groups](#diagnostic-highlighting-groups)
 - [Commands](#commands)
     - [YcmCompleter subcommands](#ycmcompleter-subcommands)
@@ -1019,15 +1018,6 @@ another (very small) Vim plugin called [ListToggle][] (which also makes it
 possible to change the height of the `locationlist` window), also written by
 yours truly.
 
-#### C# Diagnostic Support
-Unlike the C-family diagnostic support, the C# diagnostic support is not a full
-compile run. Instead, it is a simple syntax check of the current file _only_.
-The `:YcmForceCompileAndDiagnostics` command also is only a simple syntax check,
-_not_ a compile. This means that only syntax errors will be displayed, and not
-semantic errors. For example, omitting the semicolon at the end of statement
-will be displayed as a diagnostic error, but using a nonexistent class or
-variable will not be.
-
 #### Diagnostic highlighting groups
 
 You can change the styling for the highlighting groups YCM uses. For the signs

doc/youcompleteme.txt

@@ -38,8 +38,7 @@ Contents ~
   9. Semantic completion for other languages |youcompleteme-semantic-completion-for-other-languages|
   10. Writing New Semantic Completers |youcompleteme-writing-new-semantic-completers|
   11. Diagnostic display                     |youcompleteme-diagnostic-display|
-   1. C# Diagnostic Support                |youcompleteme-c-diagnostic-support|
-   2. Diagnostic highlighting groups |youcompleteme-diagnostic-highlighting-groups|
+   1. Diagnostic highlighting groups |youcompleteme-diagnostic-highlighting-groups|
  6. Commands                                           |youcompleteme-commands|
   1. The |:YcmRestartServer| command
   2. The |:YcmForceCompileAndDiagnostics| command
@@ -188,7 +187,6 @@ Image: Build Status [1] Image: Build status [3]
   - Semantic completion for other languages
   - Writing new semantic completers
   - Diagnostic display
-  - C# diagnostic support
   - Diagnostic highlighting groups
 
 - Commands
@@ -1278,18 +1276,6 @@ another (very small) Vim plugin called ListToggle [44] (which also makes it
 possible to change the height of the 'locationlist' window), also written by
 yours truly.
 
--------------------------------------------------------------------------------
-                                           *youcompleteme-c-diagnostic-support*
-C# Diagnostic Support ~
-
-Unlike the C-family diagnostic support, the C# diagnostic support is not a full
-compile run. Instead, it is a simple syntax check of the current file _only_.
-The |:YcmForceCompileAndDiagnostics| command also is only a simple syntax
-check, _not_ a compile. This means that only syntax errors will be displayed,
-and not semantic errors. For example, omitting the semicolon at the end of
-statement will be displayed as a diagnostic error, but using a nonexistent
-class or variable will not be.
-
 -------------------------------------------------------------------------------
                                  *youcompleteme-diagnostic-highlighting-groups*
 Diagnostic highlighting groups ~